21309969600 has 126 divisors (see below), whose sum is σ = 75740714660. Its totient is φ = 5682654720.

The previous prime is 21309969599. The next prime is 21309969641. The reversal of 21309969600 is 696990312.

It is a happy number.

21309969600 is a `hidden beast` number, since 2 + 1 + 30 + 9 + 9 + 6 + 9 + 600 = 666.

It is a super-2 number, since 2×21309969600² (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 17 ways as a sum of consecutive naturals, for example, 725530 + ... + 754329.

Almost surely, 2^21309969600 is an apocalyptic number.

21309969600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21309969600 is an abundant number, since it is smaller than the sum of its proper divisors (54430745060).

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

21309969600 is a wasteful number, since it uses less digits than its factorization.

21309969600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1479887 (or 1479869 counting only the distinct ones).

The product of its (nonzero) digits is 157464, while the sum is 45.

The spelling of 21309969600 in words is "twenty-one billion, three hundred nine million, nine hundred sixty-nine thousand, six hundred".