21481772 has 12 divisors (see below), whose sum is σ = 40484976. Its totient is φ = 9914640.

The previous prime is 21481771. The next prime is 21481787. The reversal of 21481772 is 27718412.

It is a happy number.

It is a super-2 number, since 2×21481772² = 922933056519968, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21481771) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 206504 + ... + 206607.

It is an arithmetic number, because the mean of its divisors is an integer number (3373748).

Almost surely, 2^21481772 is an apocalyptic number.

It is an amenable number.

21481772 is a deficient number, since it is larger than the sum of its proper divisors (19003204).

21481772 is a wasteful number, since it uses less digits than its factorization.

21481772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 413128 (or 413126 counting only the distinct ones).

The product of its digits is 6272, while the sum is 32.

The square root of 21481772 is about 4634.8432551706. The cubic root of 21481772 is about 277.9862836771.

The spelling of 21481772 in words is "twenty-one million, four hundred eighty-one thousand, seven hundred seventy-two".