20915825 has 24 divisors (see below), whose sum is σ = 29944512. Its totient is φ = 14195520.

The previous prime is 20915777. The next prime is 20915833. The reversal of 20915825 is 52851902.

It is not a de Polignac number, because 20915825 - 2¹² = 20911729 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20915791 and 20915800.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18167 + ... + 19283.

It is an arithmetic number, because the mean of its divisors is an integer number (1247688).

Almost surely, 2^20915825 is an apocalyptic number.

20915825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20915825 is a deficient number, since it is larger than the sum of its proper divisors (9028687).

20915825 is a wasteful number, since it uses less digits than its factorization.

20915825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1241 (or 1236 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 32.

The square root of 20915825 is about 4573.3822276298. The cubic root of 20915825 is about 275.5233010925.

It can be divided in two parts, 20915 and 825, that multiplied together give a triangular number (17254875 = T₅₈₇₄).

The spelling of 20915825 in words is "twenty million, nine hundred fifteen thousand, eight hundred twenty-five".