21020121210 has 48 divisors (see below), whose sum is σ = 55451436768. Its totient is φ = 5095786080.

The previous prime is 21020121197. The next prime is 21020121229. The reversal of 21020121210 is 1212102012.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2891704 + ... + 2898963.

It is an arithmetic number, because the mean of its divisors is an integer number (1155238266).

Almost surely, 2^21020121210 is an apocalyptic number.

21020121210 is an abundant number, since it is smaller than the sum of its proper divisors (34431315558).

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

21020121210 is a wasteful number, since it uses less digits than its factorization.

21020121210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5790699 (or 5790688 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21020121210 its reverse (1212102012), we get a palindrome (22232223222).

The spelling of 21020121210 in words is "twenty-one billion, twenty million, one hundred twenty-one thousand, two hundred ten".