20001202121 has 4 divisors (see below), whose sum is σ = 20001793812. Its totient is φ = 20000610432.

The previous prime is 20001202057. The next prime is 20001202127. The reversal of 20001202121 is 12120210002.

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 15822872521 + 4178329600 = 125789^2 + 64640^2 .

It is a cyclic number.

It is not a de Polignac number, because 20001202121 - 2⁶ = 20001202057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20001202127) 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, 241856 + ... + 313841.

It is an arithmetic number, because the mean of its divisors is an integer number (5000448453).

Almost surely, 2^20001202121 is an apocalyptic number.

It is an amenable number.

20001202121 is a deficient number, since it is larger than the sum of its proper divisors (591691).

20001202121 is an equidigital number, since it uses as much as digits as its factorization.

20001202121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 591690.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 20001202121 its reverse (12120210002), we get a palindrome (32121412123).

The spelling of 20001202121 in words is "twenty billion, one million, two hundred two thousand, one hundred twenty-one".