21221020102020 has 48 divisors (see below), whose sum is σ = 59419079435520. Its totient is φ = 5658917441536.

The previous prime is 21221020102001. The next prime is 21221020102039. The reversal of 21221020102020 is 2020102012212.

It is an interprime number because it is at equal distance from previous prime (21221020102001) and next prime (21221020102039).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21630901 + ... + 22590659.

It is an arithmetic number, because the mean of its divisors is an integer number (1237897488240).

Almost surely, 2^{21221020102020} is an apocalyptic number.

21221020102020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221020102020 is an abundant number, since it is smaller than the sum of its proper divisors (38198059333500).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21221020102020 is a wasteful number, since it uses less digits than its factorization.

21221020102020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1328284 (or 1328282 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21221020102020 its reverse (2020102012212), we get a palindrome (23241122114232).

The spelling of 21221020102020 in words is "twenty-one trillion, two hundred twenty-one billion, twenty million, one hundred two thousand, twenty".