21777072 has 40 divisors (see below), whose sum is σ = 56424960. Its totient is φ = 7237440.

The previous prime is 21777043. The next prime is 21777073. The reversal of 21777072 is 27077712.

It is not an unprimeable number, because it can be changed into a prime (21777073) 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, 29929 + ... + 30647.

It is an arithmetic number, because the mean of its divisors is an integer number (1410624).

Almost surely, 2^21777072 is an apocalyptic number.

It is an amenable number.

21777072 is an abundant number, since it is smaller than the sum of its proper divisors (34647888).

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

21777072 is a wasteful number, since it uses less digits than its factorization.

21777072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1361 (or 1355 counting only the distinct ones).

The product of its (nonzero) digits is 9604, while the sum is 33.

The square root of 21777072 is about 4666.5910470064. The cubic root of 21777072 is about 279.2542741701.

The spelling of 21777072 in words is "twenty-one million, seven hundred seventy-seven thousand, seventy-two".