21400776 has 24 divisors (see below), whose sum is σ = 57960630. Its totient is φ = 7133568.

The previous prime is 21400751. The next prime is 21400781. The reversal of 21400776 is 67700412.

It can be written as a sum of positive squares in only one way, i.e., 21399876 + 900 = 4626^2 + 30^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 148545 + ... + 148688.

Almost surely, 2^21400776 is an apocalyptic number.

It is an amenable number.

21400776 is an abundant number, since it is smaller than the sum of its proper divisors (36559854).

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

21400776 is a wasteful number, since it uses less digits than its factorization.

21400776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297245 (or 297238 counting only the distinct ones).

The product of its (nonzero) digits is 2352, while the sum is 27.

The square root of 21400776 is about 4626.0972752418. The cubic root of 21400776 is about 277.6364656285.

The spelling of 21400776 in words is "twenty-one million, four hundred thousand, seven hundred seventy-six".