21016625 has 16 divisors (see below), whose sum is σ = 29976960. Its totient is φ = 14410800.

The previous prime is 21016613. The next prime is 21016631. The reversal of 21016625 is 52661012.

It is not a de Polignac number, because 21016625 - 2⁴ = 21016609 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21016625.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11135 + ... + 12884.

It is an arithmetic number, because the mean of its divisors is an integer number (1873560).

Almost surely, 2^21016625 is an apocalyptic number.

21016625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21016625 is a deficient number, since it is larger than the sum of its proper divisors (8960335).

21016625 is an equidigital number, since it uses as much as digits as its factorization.

21016625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24041 (or 24031 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 21016625 is about 4584.3892723023. The cubic root of 21016625 is about 275.9652033777.

Adding to 21016625 its reverse (52661012), we get a palindrome (73677637).

The spelling of 21016625 in words is "twenty-one million, sixteen thousand, six hundred twenty-five".