21210021021220 has 24 divisors (see below), whose sum is σ = 44564400828864. Its totient is φ = 8479559516256.

The previous prime is 21210021021197. The next prime is 21210021021263. The reversal of 21210021021220 is 2212012001212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21210021021194 and 21210021021203.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 278016672 + ... + 278092951.

It is an arithmetic number, because the mean of its divisors is an integer number (1856850034536).

Almost surely, 2^{21210021021220} is an apocalyptic number.

21210021021220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210021021220 is an abundant number, since it is smaller than the sum of its proper divisors (23354379807644).

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

21210021021220 is a wasteful number, since it uses less digits than its factorization.

21210021021220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 556111539 (or 556111537 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21210021021220 its reverse (2212012001212), we get a palindrome (23422033022432).

The spelling of 21210021021220 in words is "twenty-one trillion, two hundred ten billion, twenty-one million, twenty-one thousand, two hundred twenty".