21726378900 has 90 divisors (see below), whose sum is σ = 70428363390. Its totient is φ = 5793698880.

The previous prime is 21726378871. The next prime is 21726378901. The reversal of 21726378900 is 987362712.

21726378900 is a `hidden beast` number, since 2 + 1 + 7 + 2 + 637 + 8 + 9 + 0 + 0 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 7190700804 + 14535678096 = 84798^2 + 120564^2 .

It is a tau number, because it is divible by the number of its divisors (90).

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21726378901) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 1333035 + ... + 1349234.

It is an arithmetic number, because the mean of its divisors is an integer number (782537371).

Almost surely, 2^21726378900 is an apocalyptic number.

21726378900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21726378900 is an abundant number, since it is smaller than the sum of its proper divisors (48701984490).

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

21726378900 is a wasteful number, since it uses less digits than its factorization.

21726378900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2682295 (or 2682279 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 45.

The spelling of 21726378900 in words is "twenty-one billion, seven hundred twenty-six million, three hundred seventy-eight thousand, nine hundred".