1256664667 has 16 divisors (see below), whose sum is σ = 1348099200. Its totient is φ = 1167281280.

The previous prime is 1256664653. The next prime is 1256664671. The reversal of 1256664667 is 7664666521.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1256664667 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1256664667.

It is not an unprimeable number, because it can be changed into a prime (1256664697) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 421492 + ... + 424462.

It is an arithmetic number, because the mean of its divisors is an integer number (84256200).

Almost surely, 2^1256664667 is an apocalyptic number.

1256664667 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

1256664667 is a deficient number, since it is larger than the sum of its proper divisors (91434533).

1256664667 is a wasteful number, since it uses less digits than its factorization.

1256664667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3306.

The product of its digits is 2177280, while the sum is 49.

The square root of 1256664667 is about 35449.4663852645. The cubic root of 1256664667 is about 1079.1284311997.

The spelling of 1256664667 in words is "one billion, two hundred fifty-six million, six hundred sixty-four thousand, six hundred sixty-seven".