25666161520 has 40 divisors (see below), whose sum is σ = 60143721984. Its totient is φ = 10185622272.

The previous prime is 25666161509. The next prime is 25666161523. The reversal of 25666161520 is 2516166652.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25666161523) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 1252939 + ... + 1273258.

Almost surely, 2^25666161520 is an apocalyptic number.

25666161520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25666161520 is an abundant number, since it is smaller than the sum of its proper divisors (34477560464).

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

25666161520 is a wasteful number, since it uses less digits than its factorization.

25666161520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2526337 (or 2526331 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 40.

The spelling of 25666161520 in words is "twenty-five billion, six hundred sixty-six million, one hundred sixty-one thousand, five hundred twenty".