21738472 has 16 divisors (see below), whose sum is σ = 46582560. Its totient is φ = 9316464.

The previous prime is 21738469. The next prime is 21738481. The reversal of 21738472 is 27483712.

It is a super-2 number, since 2×21738472² = 945122329789568, which contains 22 as substring.

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, 194038 + ... + 194149.

It is an arithmetic number, because the mean of its divisors is an integer number (2911410).

Almost surely, 2^21738472 is an apocalyptic number.

It is an amenable number.

21738472 is an abundant number, since it is smaller than the sum of its proper divisors (24844088).

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

21738472 is a wasteful number, since it uses less digits than its factorization.

21738472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388200 (or 388196 counting only the distinct ones).

The product of its digits is 18816, while the sum is 34.

The square root of 21738472 is about 4662.4534314028. The cubic root of 21738472 is about 279.0891832585.

The spelling of 21738472 in words is "twenty-one million, seven hundred thirty-eight thousand, four hundred seventy-two".