21481588 has 12 divisors (see below), whose sum is σ = 37723140. Its totient is φ = 10703552.

The previous prime is 21481567. The next prime is 21481597. The reversal of 21481588 is 88518412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 16337764 + 5143824 = 4042^2 + 2268^2 .

It is a super-2 number, since 2×21481588² = 922917246003488, 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, 7993 + ... + 10336.

It is an arithmetic number, because the mean of its divisors is an integer number (3143595).

Almost surely, 2^21481588 is an apocalyptic number.

It is an amenable number.

21481588 is a deficient number, since it is larger than the sum of its proper divisors (16241552).

21481588 is a wasteful number, since it uses less digits than its factorization.

21481588 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18626 (or 18624 counting only the distinct ones).

The product of its digits is 20480, while the sum is 37.

The square root of 21481588 is about 4634.8234054816. The cubic root of 21481588 is about 277.9854899868.

The spelling of 21481588 in words is "twenty-one million, four hundred eighty-one thousand, five hundred eighty-eight".