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20202121220021 = 131554009324617
BaseRepresentation
bin1001001011111101011000…
…10000100100111110110101
32122112022012120012022222122
410211332230100210332311
510121442421013020041
6110544420521205325
74153361253032546
oct445765420447665
978468176168878
1020202121220021
116489742840234
122323381630845
13b37089c10590
144dbb05d504cd
15250784664c4b
hex125fac424fb5

20202121220021 has 4 divisors (see below), whose sum is σ = 21756130544652. Its totient is φ = 18648111895392.

The previous prime is 20202121220003. The next prime is 20202121220027. The reversal of 20202121220021 is 12002212120202.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4004957535121 + 16197163684900 = 2001239^2 + 4024570^2 .

It is a cyclic number.

It is not a de Polignac number, because 20202121220021 - 214 = 20202121203637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20202121220027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 777004662296 + ... + 777004662321.

It is an arithmetic number, because the mean of its divisors is an integer number (5439032636163).

Almost surely, 220202121220021 is an apocalyptic number.

It is an amenable number.

20202121220021 is a deficient number, since it is larger than the sum of its proper divisors (1554009324631).

20202121220021 is a wasteful number, since it uses less digits than its factorization.

20202121220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1554009324630.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 20202121220021 its reverse (12002212120202), we get a palindrome (32204333340223).

The spelling of 20202121220021 in words is "twenty trillion, two hundred two billion, one hundred twenty-one million, two hundred twenty thousand, twenty-one".

Divisors: 1 13 1554009324617 20202121220021