21687174 has 24 divisors (see below), whose sum is σ = 47199672. Its totient is φ = 7196640.

The previous prime is 21687119. The next prime is 21687191. The reversal of 21687174 is 47178612.

It is a super-2 number, since 2×21687174² = 940667032212552, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1609 + ... + 6779.

It is an arithmetic number, because the mean of its divisors is an integer number (1966653).

Almost surely, 2^21687174 is an apocalyptic number.

21687174 is an abundant number, since it is smaller than the sum of its proper divisors (25512498).

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

21687174 is a wasteful number, since it uses less digits than its factorization.

21687174 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5412 (or 5409 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 21687174 is about 4656.9490012239. The cubic root of 21687174 is about 278.8694807094.

The spelling of 21687174 in words is "twenty-one million, six hundred eighty-seven thousand, one hundred seventy-four".