1264415561 has 4 divisors (see below), whose sum is σ = 1264499712. Its totient is φ = 1264331412.

The previous prime is 1264415557. The next prime is 1264415701. The reversal of 1264415561 is 1655144621.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1264415561 - 2² = 1264415557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1264415521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12701 + ... + 51866.

It is an arithmetic number, because the mean of its divisors is an integer number (316124928).

Almost surely, 2^1264415561 is an apocalyptic number.

It is an amenable number.

1264415561 is a deficient number, since it is larger than the sum of its proper divisors (84151).

1264415561 is an equidigital number, since it uses as much as digits as its factorization.

1264415561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84150.

The product of its digits is 28800, while the sum is 35.

The square root of 1264415561 is about 35558.6214721550. The cubic root of 1264415561 is about 1081.3425122889.

The spelling of 1264415561 in words is "one billion, two hundred sixty-four million, four hundred fifteen thousand, five hundred sixty-one".