21577072 has 20 divisors (see below), whose sum is σ = 45606456. Its totient is φ = 9807680.

The previous prime is 21577069. The next prime is 21577091. The reversal of 21577072 is 27077512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61123 + ... + 61474.

Almost surely, 2^21577072 is an apocalyptic number.

21577072 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21577072 is an abundant number, since it is smaller than the sum of its proper divisors (24029384).

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

21577072 is a wasteful number, since it uses less digits than its factorization.

21577072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122616 (or 122610 counting only the distinct ones).

The product of its (nonzero) digits is 6860, while the sum is 31.

The square root of 21577072 is about 4645.1127004627. The cubic root of 21577072 is about 278.3967559185.

It can be divided in two parts, 2157 and 7072, that added together give a palindrome (9229).

The spelling of 21577072 in words is "twenty-one million, five hundred seventy-seven thousand, seventy-two".