21020212120 has 16 divisors (see below), whose sum is σ = 47295477360. Its totient is φ = 8408084832.

The previous prime is 21020212111. The next prime is 21020212121. The reversal of 21020212120 is 2121202012.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21020212120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020212121) 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, 262752612 + ... + 262752691.

It is an arithmetic number, because the mean of its divisors is an integer number (2955967335).

Almost surely, 2^21020212120 is an apocalyptic number.

21020212120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21020212120 is an abundant number, since it is smaller than the sum of its proper divisors (26275265240).

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

21020212120 is a wasteful number, since it uses less digits than its factorization.

21020212120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 525505314 (or 525505310 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21020212120 its reverse (2121202012), we get a palindrome (23141414132).

The spelling of 21020212120 in words is "twenty-one billion, twenty million, two hundred twelve thousand, one hundred twenty".