21874728 has 32 divisors (see below), whose sum is σ = 55224000. Its totient is φ = 7219968.

The previous prime is 21874711. The next prime is 21874751. The reversal of 21874728 is 82747812.

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, 1953 + ... + 6896.

It is an arithmetic number, because the mean of its divisors is an integer number (1725750).

Almost surely, 2^21874728 is an apocalyptic number.

It is an amenable number.

21874728 is an abundant number, since it is smaller than the sum of its proper divisors (33349272).

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

21874728 is a wasteful number, since it uses less digits than its factorization.

21874728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8961 (or 8957 counting only the distinct ones).

The product of its digits is 50176, while the sum is 39.

The square root of 21874728 is about 4677.0426553539. The cubic root of 21874728 is about 279.6710763407.

The spelling of 21874728 in words is "twenty-one million, eight hundred seventy-four thousand, seven hundred twenty-eight".