1265044661 has 4 divisors (see below), whose sum is σ = 1277326752. Its totient is φ = 1252762572.

The previous prime is 1265044633. The next prime is 1265044687. The reversal of 1265044661 is 1664405621.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1265044661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265044601) 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, 6140891 + ... + 6141096.

It is an arithmetic number, because the mean of its divisors is an integer number (319331688).

Almost surely, 2^1265044661 is an apocalyptic number.

It is an amenable number.

1265044661 is a deficient number, since it is larger than the sum of its proper divisors (12282091).

1265044661 is a wasteful number, since it uses less digits than its factorization.

1265044661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12282090.

The product of its (nonzero) digits is 34560, while the sum is 35.

The square root of 1265044661 is about 35567.4663280926. The cubic root of 1265044661 is about 1081.5218203701.

The spelling of 1265044661 in words is "one billion, two hundred sixty-five million, forty-four thousand, six hundred sixty-one".