1265512661 has 12 divisors (see below), whose sum is σ = 1506364992. Its totient is φ = 1059497208.

The previous prime is 1265512621. The next prime is 1265512663. The reversal of 1265512661 is 1662155621.

It is a de Polignac number, because none of the positive numbers 2^k-1265512661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265512663) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 298205 + ... + 302418.

It is an arithmetic number, because the mean of its divisors is an integer number (125530416).

Almost surely, 2^1265512661 is an apocalyptic number.

It is an amenable number.

1265512661 is a deficient number, since it is larger than the sum of its proper divisors (240852331).

1265512661 is an equidigital number, since it uses as much as digits as its factorization.

1265512661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 600680 (or 600673 counting only the distinct ones).

The product of its digits is 21600, while the sum is 35.

The square root of 1265512661 is about 35574.0447658121. The cubic root of 1265512661 is about 1081.6551726602.

The spelling of 1265512661 in words is "one billion, two hundred sixty-five million, five hundred twelve thousand, six hundred sixty-one".