21086020 has 12 divisors (see below), whose sum is σ = 44280684. Its totient is φ = 8434400.

The previous prime is 21086017. The next prime is 21086027. The reversal of 21086020 is 2068012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 10536516 + 10549504 = 3246^2 + 3248^2 .

It is not an unprimeable number, because it can be changed into a prime (21086027) 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, 527131 + ... + 527170.

It is an arithmetic number, because the mean of its divisors is an integer number (3690057).

Almost surely, 2^21086020 is an apocalyptic number.

21086020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21086020 is an abundant number, since it is smaller than the sum of its proper divisors (23194664).

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

21086020 is a wasteful number, since it uses less digits than its factorization.

21086020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1054310 (or 1054308 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 21086020 is about 4591.9516547978. The cubic root of 21086020 is about 276.2686070880.

It can be divided in two parts, 2108 and 6020, that added together give a triangular number (8128 = T₁₂₇).

The spelling of 21086020 in words is "twenty-one million, eighty-six thousand, twenty".