21757672 has 8 divisors (see below), whose sum is σ = 40795650. Its totient is φ = 10878832.

The previous prime is 21757669. The next prime is 21757693. The reversal of 21757672 is 27675712.

It can be written as a sum of positive squares in only one way, i.e., 18610596 + 3147076 = 4314^2 + 1774^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1359847 + ... + 1359862.

Almost surely, 2^21757672 is an apocalyptic number.

It is an amenable number.

21757672 is a deficient number, since it is larger than the sum of its proper divisors (19037978).

21757672 is a wasteful number, since it uses less digits than its factorization.

21757672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2719715 (or 2719711 counting only the distinct ones).

The product of its digits is 41160, while the sum is 37.

The square root of 21757672 is about 4664.5119787605. The cubic root of 21757672 is about 279.1713254241.

It can be divided in two parts, 2175767 and 2, that multiplied together give a palindrome (4351534).

The spelling of 21757672 in words is "twenty-one million, seven hundred fifty-seven thousand, six hundred seventy-two".