25665279920 has 80 divisors (see below), whose sum is σ = 69018082560. Its totient is φ = 8693490432.

The previous prime is 25665279911. The next prime is 25665279943. The reversal of 25665279920 is 2997256652.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 229610 + ... + 322569.

It is an arithmetic number, because the mean of its divisors is an integer number (862726032).

Almost surely, 2^25665279920 is an apocalyptic number.

25665279920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25665279920 is an abundant number, since it is smaller than the sum of its proper divisors (43352802640).

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

25665279920 is a wasteful number, since it uses less digits than its factorization.

25665279920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 552282 (or 552276 counting only the distinct ones).

The product of its (nonzero) digits is 4082400, while the sum is 53.

The spelling of 25665279920 in words is "twenty-five billion, six hundred sixty-five million, two hundred seventy-nine thousand, nine hundred twenty".