21588340 has 12 divisors (see below), whose sum is σ = 45335556. Its totient is φ = 8635328.

The previous prime is 21588299. The next prime is 21588361. The reversal of 21588340 is 4388512.

It can be written as a sum of positive squares in 2 ways, for example, as 4892944 + 16695396 = 2212^2 + 4086^2 .

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, 539689 + ... + 539728.

It is an arithmetic number, because the mean of its divisors is an integer number (3777963).

Almost surely, 2^21588340 is an apocalyptic number.

21588340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21588340 is an abundant number, since it is smaller than the sum of its proper divisors (23747216).

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

21588340 is a wasteful number, since it uses less digits than its factorization.

21588340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1079426 (or 1079424 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 21588340 is about 4646.3254298424. The cubic root of 21588340 is about 278.4452090287.

The spelling of 21588340 in words is "twenty-one million, five hundred eighty-eight thousand, three hundred forty".