20515825 has 24 divisors (see below), whose sum is σ = 28230336. Its totient is φ = 14664000.

The previous prime is 20515819. The next prime is 20515837. The reversal of 20515825 is 52851502.

It is not a de Polignac number, because 20515825 - 2¹⁷ = 20384753 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20515793 and 20515802.

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 23 ways as a sum of consecutive naturals, for example, 16164 + ... + 17386.

It is an arithmetic number, because the mean of its divisors is an integer number (1176264).

Almost surely, 2^20515825 is an apocalyptic number.

20515825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20515825 is a deficient number, since it is larger than the sum of its proper divisors (7714511).

20515825 is a wasteful number, since it uses less digits than its factorization.

20515825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1305 (or 1300 counting only the distinct ones).

The product of its (nonzero) digits is 4000, while the sum is 28.

The square root of 20515825 is about 4529.4398108375. The cubic root of 20515825 is about 273.7555894969.

The spelling of 20515825 in words is "twenty million, five hundred fifteen thousand, eight hundred twenty-five".