21084625 has 8 divisors (see below), whose sum is σ = 26313768. Its totient is φ = 16867600.

The previous prime is 21084611. The next prime is 21084631. The reversal of 21084625 is 52648012.

It can be written as a sum of positive squares in 4 ways, for example, as 3845521 + 17239104 = 1961^2 + 4152^2 .

It is not a de Polignac number, because 21084625 - 2⁵ = 21084593 is a prime.

It is a super-2 number, since 2×21084625² = 889122822781250, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21084593 and 21084602.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 84214 + ... + 84463.

It is an arithmetic number, because the mean of its divisors is an integer number (3289221).

Almost surely, 2^21084625 is an apocalyptic number.

21084625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21084625 is a deficient number, since it is larger than the sum of its proper divisors (5229143).

21084625 is an equidigital number, since it uses as much as digits as its factorization.

21084625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168692 (or 168682 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 21084625 is about 4591.7997560869. The cubic root of 21084625 is about 276.2625145331.

The spelling of 21084625 in words is "twenty-one million, eighty-four thousand, six hundred twenty-five".