265601891 has 2 divisors, whose sum is σ = 265601892. Its totient is φ = 265601890.

The previous prime is 265601881. The next prime is 265601939. The reversal of 265601891 is 198106562.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 265601891 - 2⁶ = 265601827 is a prime.

It is not a weakly prime, because it can be changed into another prime (265601851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 132800945 + 132800946.

It is an arithmetic number, because the mean of its divisors is an integer number (132800946).

Almost surely, 2^265601891 is an apocalyptic number.

265601891 is a deficient number, since it is larger than the sum of its proper divisors (1).

265601891 is an equidigital number, since it uses as much as digits as its factorization.

265601891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 265601891 is about 16297.2970458294. The cubic root of 265601891 is about 642.8017556349.

The spelling of 265601891 in words is "two hundred sixty-five million, six hundred one thousand, eight hundred ninety-one".