265663640 has 32 divisors (see below), whose sum is σ = 652084560. Its totient is φ = 96604800.

The previous prime is 265663637. The next prime is 265663667. The reversal of 265663640 is 46366562.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 265663594 and 265663603.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 301451 + ... + 302330.

Almost surely, 2^265663640 is an apocalyptic number.

265663640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

265663640 is an abundant number, since it is smaller than the sum of its proper divisors (386420920).

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

265663640 is a wasteful number, since it uses less digits than its factorization.

265663640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603803 (or 603799 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 38.

The square root of 265663640 is about 16299.1913909862. The cubic root of 265663640 is about 642.8515661362.

The spelling of 265663640 in words is "two hundred sixty-five million, six hundred sixty-three thousand, six hundred forty".