25649820 has 72 divisors (see below), whose sum is σ = 88923744. Its totient is φ = 5862528.

The previous prime is 25649783. The next prime is 25649831. The reversal of 25649820 is 2894652.

It is a happy number.

25649820 is a `hidden beast` number, since 2 + 5 + 649 + 8 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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, 8919 + ... + 11438.

It is an arithmetic number, because the mean of its divisors is an integer number (1235052).

Almost surely, 2^25649820 is an apocalyptic number.

25649820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25649820 is an abundant number, since it is smaller than the sum of its proper divisors (63273924).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25649820 is a wasteful number, since it uses less digits than its factorization.

25649820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20379 (or 20374 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 25649820 is about 5064.5651343427. The cubic root of 25649820 is about 294.9135818879.

The spelling of 25649820 in words is "twenty-five million, six hundred forty-nine thousand, eight hundred twenty".