21502525 has 12 divisors (see below), whose sum is σ = 29087424. Its totient is φ = 15638000.

The previous prime is 21502469. The next prime is 21502531. The reversal of 21502525 is 52520512.

It is not a de Polignac number, because 21502525 - 2¹¹ = 21500477 is a prime.

It is a Duffinian number.

21502525 is a modest number, since divided by 2525 gives 2150 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 21502496 and 21502505.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 38821 + ... + 39370.

It is an arithmetic number, because the mean of its divisors is an integer number (2423952).

Almost surely, 2^21502525 is an apocalyptic number.

21502525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21502525 is a deficient number, since it is larger than the sum of its proper divisors (7584899).

21502525 is a wasteful number, since it uses less digits than its factorization.

21502525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78212 (or 78207 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 22.

The square root of 21502525 is about 4637.0815175065. The cubic root of 21502525 is about 278.0757733859.

The spelling of 21502525 in words is "twenty-one million, five hundred two thousand, five hundred twenty-five".