21893487 has 16 divisors (see below), whose sum is σ = 36394752. Its totient is φ = 11373120.

The previous prime is 21893483. The next prime is 21893513. The reversal of 21893487 is 78439812.

It is not a de Polignac number, because 21893487 - 2² = 21893483 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21893483) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 47158 + ... + 47619.

It is an arithmetic number, because the mean of its divisors is an integer number (2274672).

Almost surely, 2^21893487 is an apocalyptic number.

21893487 is a deficient number, since it is larger than the sum of its proper divisors (14501265).

21893487 is a wasteful number, since it uses less digits than its factorization.

21893487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94798.

The product of its digits is 96768, while the sum is 42.

The square root of 21893487 is about 4679.0476595136. The cubic root of 21893487 is about 279.7509988696.

The spelling of 21893487 in words is "twenty-one million, eight hundred ninety-three thousand, four hundred eighty-seven".