21213213020 has 24 divisors (see below), whose sum is σ = 47168203824. Its totient is φ = 7986150656.

The previous prime is 21213213019. The next prime is 21213213023. The reversal of 21213213020 is 2031231212.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a self number, because there is not a number n which added to its sum of digits gives 21213213020.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213213023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31195562 + ... + 31196241.

It is an arithmetic number, because the mean of its divisors is an integer number (1965341826).

Almost surely, 2^21213213020 is an apocalyptic number.

21213213020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21213213020 is an abundant number, since it is smaller than the sum of its proper divisors (25954990804).

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

21213213020 is a wasteful number, since it uses less digits than its factorization.

21213213020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62391829 (or 62391827 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21213213020 its reverse (2031231212), we get a palindrome (23244444232).

The spelling of 21213213020 in words is "twenty-one billion, two hundred thirteen million, two hundred thirteen thousand, twenty".