21677772 has 24 divisors (see below), whose sum is σ = 51057216. Its totient is φ = 7157968.

The previous prime is 21677741. The next prime is 21677779. The reversal of 21677772 is 27777612.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21677772.

It is not an unprimeable number, because it can be changed into a prime (21677779) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7158 + ... + 9725.

It is an arithmetic number, because the mean of its divisors is an integer number (2127384).

Almost surely, 2^21677772 is an apocalyptic number.

It is an amenable number.

21677772 is an abundant number, since it is smaller than the sum of its proper divisors (29379444).

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

21677772 is a wasteful number, since it uses less digits than its factorization.

21677772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16997 (or 16995 counting only the distinct ones).

The product of its digits is 57624, while the sum is 39.

The square root of 21677772 is about 4655.9394325957. The cubic root of 21677772 is about 278.8291756295.

The spelling of 21677772 in words is "twenty-one million, six hundred seventy-seven thousand, seven hundred seventy-two".