1265731761 has 32 divisors (see below), whose sum is σ = 2002157568. Its totient is φ = 696248640.

The previous prime is 1265731751. The next prime is 1265731771. The reversal of 1265731761 is 1671375621.

It is an interprime number because it is at equal distance from previous prime (1265731751) and next prime (1265731771).

It is not a de Polignac number, because 1265731761 - 2⁵ = 1265731729 is a prime.

It is a super-2 number, since 2×1265731761² = 3204153781608322242, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1265731711) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 49696 + ... + 70718.

It is an arithmetic number, because the mean of its divisors is an integer number (62567424).

Almost surely, 2^1265731761 is an apocalyptic number.

It is an amenable number.

1265731761 is a deficient number, since it is larger than the sum of its proper divisors (736425807).

1265731761 is a wasteful number, since it uses less digits than its factorization.

1265731761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21141.

The product of its digits is 52920, while the sum is 39.

The square root of 1265731761 is about 35577.1241249205. The cubic root of 1265731761 is about 1081.7175918890.

The spelling of 1265731761 in words is "one billion, two hundred sixty-five million, seven hundred thirty-one thousand, seven hundred sixty-one".