21012021210 has 128 divisors (see below), whose sum is σ = 51734225664. Its totient is φ = 5460848640.

The previous prime is 21012021209. The next prime is 21012021221. The reversal of 21012021210 is 1212021012.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 87186690 + ... + 87186930.

It is an arithmetic number, because the mean of its divisors is an integer number (404173638).

Almost surely, 2^21012021210 is an apocalyptic number.

21012021210 is an abundant number, since it is smaller than the sum of its proper divisors (30722204454).

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

21012021210 is a wasteful number, since it uses less digits than its factorization.

21012021210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 688.

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

Adding to 21012021210 its reverse (1212021012), we get a palindrome (22224042222).

The spelling of 21012021210 in words is "twenty-one billion, twelve million, twenty-one thousand, two hundred ten".