21271590 has 48 divisors (see below), whose sum is σ = 58563648. Its totient is φ = 5338368.

The previous prime is 21271567. The next prime is 21271637. The reversal of 21271590 is 9517212.

21271590 is a `hidden beast` number, since 2 + 1 + 2 + 71 + 590 = 666.

It is a super-2 number, since 2×21271590² = 904961082256200, 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 23 ways as a sum of consecutive naturals, for example, 5422 + ... + 8481.

It is an arithmetic number, because the mean of its divisors is an integer number (1220076).

Almost surely, 2^21271590 is an apocalyptic number.

21271590 is an abundant number, since it is smaller than the sum of its proper divisors (37292058).

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

21271590 is a wasteful number, since it uses less digits than its factorization.

21271590 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13933 (or 13930 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 21271590 is about 4612.1133984324. The cubic root of 21271590 is about 277.0766859669.

The spelling of 21271590 in words is "twenty-one million, two hundred seventy-one thousand, five hundred ninety".