21085854 has 16 divisors (see below), whose sum is σ = 42230160. Its totient is φ = 7018880.

The previous prime is 21085853. The next prime is 21085879. The reversal of 21085854 is 45858012.

It is a super-2 number, since 2×21085854² = 889226477818632, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21085853) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3292 + ... + 7280.

It is an arithmetic number, because the mean of its divisors is an integer number (2639385).

Almost surely, 2^21085854 is an apocalyptic number.

21085854 is an abundant number, since it is smaller than the sum of its proper divisors (21144306).

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

21085854 is a wasteful number, since it uses less digits than its factorization.

21085854 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4875.

The product of its (nonzero) digits is 12800, while the sum is 33.

The square root of 21085854 is about 4591.9335796590. The cubic root of 21085854 is about 276.2678821099.

The spelling of 21085854 in words is "twenty-one million, eighty-five thousand, eight hundred fifty-four".