21001818620 has 48 divisors (see below), whose sum is σ = 45549638400. Its totient is φ = 8125608960.

The previous prime is 21001818611. The next prime is 21001818689. The reversal of 21001818620 is 2681810012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1399316 + ... + 1414244.

It is an arithmetic number, because the mean of its divisors is an integer number (948950800).

Almost surely, 2^21001818620 is an apocalyptic number.

21001818620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001818620 is an abundant number, since it is smaller than the sum of its proper divisors (24547819780).

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

21001818620 is a wasteful number, since it uses less digits than its factorization.

21001818620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17238 (or 17236 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 29.

The spelling of 21001818620 in words is "twenty-one billion, one million, eight hundred eighteen thousand, six hundred twenty".