21612162020 has 24 divisors (see below), whose sum is σ = 45712060800. Its totient is φ = 8582670432.

The previous prime is 21612162001. The next prime is 21612162053. The reversal of 21612162020 is 2026121612.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3884300 + ... + 3889859.

It is an arithmetic number, because the mean of its divisors is an integer number (1904669200).

Almost surely, 2^21612162020 is an apocalyptic number.

21612162020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21612162020 is an abundant number, since it is smaller than the sum of its proper divisors (24099898780).

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

21612162020 is a wasteful number, since it uses less digits than its factorization.

21612162020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7774307 (or 7774305 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

Adding to 21612162020 its reverse (2026121612), we get a palindrome (23638283632).

The spelling of 21612162020 in words is "twenty-one billion, six hundred twelve million, one hundred sixty-two thousand, twenty".