20505725 has 12 divisors (see below), whose sum is σ = 26248320. Its totient is φ = 15874800.

The previous prime is 20505713. The next prime is 20505761. The reversal of 20505725 is 52750502.

It is not a de Polignac number, because 20505725 - 2⁸ = 20505469 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20505694 and 20505703.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12455 + ... + 14004.

It is an arithmetic number, because the mean of its divisors is an integer number (2187360).

Almost surely, 2^20505725 is an apocalyptic number.

20505725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20505725 is a deficient number, since it is larger than the sum of its proper divisors (5742595).

20505725 is a wasteful number, since it uses less digits than its factorization.

20505725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26500 (or 26495 counting only the distinct ones).

The product of its (nonzero) digits is 3500, while the sum is 26.

The square root of 20505725 is about 4528.3247454219. The cubic root of 20505725 is about 273.7106585666.

The spelling of 20505725 in words is "twenty million, five hundred five thousand, seven hundred twenty-five".