21247854 has 16 divisors (see below), whose sum is σ = 43400448. Its totient is φ = 6931832.

The previous prime is 21247843. The next prime is 21247861. The reversal of 21247854 is 45874212.

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 7 ways as a sum of consecutive naturals, for example, 37392 + ... + 37955.

It is an arithmetic number, because the mean of its divisors is an integer number (2712528).

Almost surely, 2^21247854 is an apocalyptic number.

21247854 is an abundant number, since it is smaller than the sum of its proper divisors (22152594).

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

21247854 is a wasteful number, since it uses less digits than its factorization.

21247854 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75399.

The product of its digits is 17920, while the sum is 33.

The square root of 21247854 is about 4609.5394563882. The cubic root of 21247854 is about 276.9735885186.

The spelling of 21247854 in words is "twenty-one million, two hundred forty-seven thousand, eight hundred fifty-four".