21535625 has 10 divisors (see below), whose sum is σ = 26911698. Its totient is φ = 17228000.

The previous prime is 21535621. The next prime is 21535639. The reversal of 21535625 is 52653512.

It is a happy number.

It can be written as a sum of positive squares in 5 ways, for example, as 7011904 + 14523721 = 2648^2 + 3811^2 .

It is not a de Polignac number, because 21535625 - 2² = 21535621 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21535621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 16604 + ... + 17853.

Almost surely, 2^21535625 is an apocalyptic number.

21535625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21535625 is a deficient number, since it is larger than the sum of its proper divisors (5376073).

21535625 is an frugal number, since it uses more digits than its factorization.

21535625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34477 (or 34462 counting only the distinct ones).

The product of its digits is 9000, while the sum is 29.

The square root of 21535625 is about 4640.6492002736. The cubic root of 21535625 is about 278.2183859277.

The spelling of 21535625 in words is "twenty-one million, five hundred thirty-five thousand, six hundred twenty-five".