21765038400 has 504 divisors, whose sum is σ = 88853491584. Its totient is φ = 4949913600.

The previous prime is 21765038389. The next prime is 21765038417. The reversal of 21765038400 is 483056712.

21765038400 is a `hidden beast` number, since 2 + 1 + 76 + 503 + 84 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (504).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 26509990 + ... + 26510810.

Almost surely, 2^21765038400 is an apocalyptic number.

21765038400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21765038400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44426745792).

21765038400 is an abundant number, since it is smaller than the sum of its proper divisors (67088453184).

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

21765038400 is a wasteful number, since it uses less digits than its factorization.

21765038400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1119 (or 1101 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The spelling of 21765038400 in words is "twenty-one billion, seven hundred sixty-five million, thirty-eight thousand, four hundred".