21816477900 has 144 divisors (see below), whose sum is σ = 80155425280. Its totient is φ = 4986619200.

The previous prime is 21816477847. The next prime is 21816477923. The reversal of 21816477900 is 977461812.

It is a happy number.

It is a super-2 number, since 2×21816477900² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 558256 + ... + 596055.

Almost surely, 2^21816477900 is an apocalyptic number.

21816477900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21816477900 is an abundant number, since it is smaller than the sum of its proper divisors (58338947380).

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

21816477900 is a wasteful number, since it uses less digits than its factorization.

21816477900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1154341 (or 1154328 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 45.

The spelling of 21816477900 in words is "twenty-one billion, eight hundred sixteen million, four hundred seventy-seven thousand, nine hundred".