21681752 has 16 divisors (see below), whose sum is σ = 40748400. Its totient is φ = 10815520.

The previous prime is 21681739. The next prime is 21681769. The reversal of 21681752 is 25718612.

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, 749 + ... + 6627.

It is an arithmetic number, because the mean of its divisors is an integer number (2546775).

Almost surely, 2^21681752 is an apocalyptic number.

It is an amenable number.

21681752 is a deficient number, since it is larger than the sum of its proper divisors (19066648).

21681752 is a wasteful number, since it uses less digits than its factorization.

21681752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6346 (or 6342 counting only the distinct ones).

The product of its digits is 6720, while the sum is 32.

The square root of 21681752 is about 4656.3668240378. The cubic root of 21681752 is about 278.8462387638.

The spelling of 21681752 in words is "twenty-one million, six hundred eighty-one thousand, seven hundred fifty-two".