1265681531 has 4 divisors (see below), whose sum is σ = 1265821752. Its totient is φ = 1265541312.

The previous prime is 1265681507. The next prime is 1265681551. The reversal of 1265681531 is 1351865621.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1265681531 - 2¹⁸ = 1265419387 is a prime.

It is a super-2 number, since 2×1265681531² = 3203899475829007922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1265681551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55565 + ... + 74958.

It is an arithmetic number, because the mean of its divisors is an integer number (316455438).

Almost surely, 2^1265681531 is an apocalyptic number.

1265681531 is a deficient number, since it is larger than the sum of its proper divisors (140221).

1265681531 is an equidigital number, since it uses as much as digits as its factorization.

1265681531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140220.

The product of its digits is 43200, while the sum is 38.

The square root of 1265681531 is about 35576.4181867709. The cubic root of 1265681531 is about 1081.7032825398.

The spelling of 1265681531 in words is "one billion, two hundred sixty-five million, six hundred eighty-one thousand, five hundred thirty-one".