21987174 has 16 divisors (see below), whose sum is σ = 47972160. Its totient is φ = 6662760.

The previous prime is 21987169. The next prime is 21987179. The reversal of 21987174 is 47178912.

It is an interprime number because it is at equal distance from previous prime (21987169) and next prime (21987179).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21987179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 166504 + ... + 166635.

It is an arithmetic number, because the mean of its divisors is an integer number (2998260).

Almost surely, 2^21987174 is an apocalyptic number.

21987174 is an abundant number, since it is smaller than the sum of its proper divisors (25984986).

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

21987174 is a wasteful number, since it uses less digits than its factorization.

21987174 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333155.

The product of its digits is 28224, while the sum is 39.

The square root of 21987174 is about 4689.0483042937. The cubic root of 21987174 is about 280.1494695158.

The spelling of 21987174 in words is "twenty-one million, nine hundred eighty-seven thousand, one hundred seventy-four".