21676525 has 12 divisors (see below), whose sum is σ = 28946932. Its totient is φ = 16007040.

The previous prime is 21676517. The next prime is 21676531. The reversal of 21676525 is 52567612.

It can be written as a sum of positive squares in 6 ways, for example, as 8874441 + 12802084 = 2979^2 + 3578^2 .

It is not a de Polignac number, because 21676525 - 2³ = 21676517 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33024 + ... + 33673.

Almost surely, 2^21676525 is an apocalyptic number.

21676525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21676525 is a deficient number, since it is larger than the sum of its proper divisors (7270407).

21676525 is a wasteful number, since it uses less digits than its factorization.

21676525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66720 (or 66715 counting only the distinct ones).

The product of its digits is 25200, while the sum is 34.

The square root of 21676525 is about 4655.8055156976. The cubic root of 21676525 is about 278.8238290368.

It can be divided in two parts, 21676 and 525, that added together give a square (22201 = 149²).

The spelling of 21676525 in words is "twenty-one million, six hundred seventy-six thousand, five hundred twenty-five".