21745772 has 24 divisors (see below), whose sum is σ = 39277056. Its totient is φ = 10528848.

The previous prime is 21745769. The next prime is 21745781. The reversal of 21745772 is 27754712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18803 + ... + 19925.

It is an arithmetic number, because the mean of its divisors is an integer number (1636544).

Almost surely, 2^21745772 is an apocalyptic number.

It is an amenable number.

21745772 is a deficient number, since it is larger than the sum of its proper divisors (17531284).

21745772 is a wasteful number, since it uses less digits than its factorization.

21745772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1277 (or 1275 counting only the distinct ones).

The product of its digits is 27440, while the sum is 35.

The square root of 21745772 is about 4663.2362153337. The cubic root of 21745772 is about 279.1204200910.

The spelling of 21745772 in words is "twenty-one million, seven hundred forty-five thousand, seven hundred seventy-two".