21085104 has 20 divisors (see below), whose sum is σ = 54469976. Its totient is φ = 7028352.

The previous prime is 21085091. The next prime is 21085109. The reversal of 21085104 is 40158012.

It is a super-2 number, since 2×21085104² = 889163221381632, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21085109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 219589 + ... + 219684.

Almost surely, 2^21085104 is an apocalyptic number.

21085104 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21085104 is an abundant number, since it is smaller than the sum of its proper divisors (33384872).

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

21085104 is a wasteful number, since it uses less digits than its factorization.

21085104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 439284 (or 439278 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 21085104 is about 4591.8519139885. The cubic root of 21085104 is about 276.2646065589.

The spelling of 21085104 in words is "twenty-one million, eighty-five thousand, one hundred four".