25515820 has 24 divisors (see below), whose sum is σ = 58454928. Its totient is φ = 9278400.

The previous prime is 25515779. The next prime is 25515823. The reversal of 25515820 is 2851552.

It is not an unprimeable number, because it can be changed into a prime (25515823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57771 + ... + 58210.

It is an arithmetic number, because the mean of its divisors is an integer number (2435622).

Almost surely, 2^25515820 is an apocalyptic number.

25515820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25515820 is an abundant number, since it is smaller than the sum of its proper divisors (32939108).

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

25515820 is a wasteful number, since it uses less digits than its factorization.

25515820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116001 (or 115999 counting only the distinct ones).

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

The square root of 25515820 is about 5051.3186397217. The cubic root of 25515820 is about 294.3991216449.

It can be divided in two parts, 25515 and 820, that added together give a triangular number (26335 = T₂₂₉).

The spelling of 25515820 in words is "twenty-five million, five hundred fifteen thousand, eight hundred twenty".