21670625 has 10 divisors (see below), whose sum is σ = 27080394. Its totient is φ = 17336000.

The previous prime is 21670609. The next prime is 21670633. The reversal of 21670625 is 52607612.

It can be written as a sum of positive squares in 5 ways, for example, as 14047504 + 7623121 = 3748^2 + 2761^2 .

It is not a de Polignac number, because 21670625 - 2⁴ = 21670609 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 16712 + ... + 17961.

Almost surely, 2^21670625 is an apocalyptic number.

21670625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21670625 is a deficient number, since it is larger than the sum of its proper divisors (5409769).

21670625 is an frugal number, since it uses more digits than its factorization.

21670625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34693 (or 34678 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 21670625 is about 4655.1718550447. The cubic root of 21670625 is about 278.7985296270.

The spelling of 21670625 in words is "twenty-one million, six hundred seventy thousand, six hundred twenty-five".