21045865400 has 96 divisors (see below), whose sum is σ = 56977201440. Its totient is φ = 7079554560.

The previous prime is 21045865387. The next prime is 21045865429. The reversal of 21045865400 is 456854012.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 67619 + ... + 216018.

It is an arithmetic number, because the mean of its divisors is an integer number (593512515).

Almost surely, 2^21045865400 is an apocalyptic number.

21045865400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21045865400 is an abundant number, since it is smaller than the sum of its proper divisors (35931336040).

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

21045865400 is a wasteful number, since it uses less digits than its factorization.

21045865400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283713 (or 283704 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 35.

The spelling of 21045865400 in words is "twenty-one billion, forty-five million, eight hundred sixty-five thousand, four hundred".