21765672 has 40 divisors (see below), whose sum is σ = 60965850. Its totient is φ = 7255008.

The previous prime is 21765647. The next prime is 21765683. The reversal of 21765672 is 27656712.

21765672 is a `hidden beast` number, since 21 + 76 + 567 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 12068676 + 9696996 = 3474^2 + 3114^2 .

It is a super-3 number, since 3×21765672³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 16147 + ... + 17442.

Almost surely, 2^21765672 is an apocalyptic number.

It is an amenable number.

21765672 is an abundant number, since it is smaller than the sum of its proper divisors (39200178).

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

21765672 is a wasteful number, since it uses less digits than its factorization.

21765672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33607 (or 33594 counting only the distinct ones).

The product of its digits is 35280, while the sum is 36.

The square root of 21765672 is about 4665.3694387476. The cubic root of 21765672 is about 279.2055370642.

The spelling of 21765672 in words is "twenty-one million, seven hundred sixty-five thousand, six hundred seventy-two".