1256645666 has 8 divisors (see below), whose sum is σ = 1885285584. Its totient is φ = 628217140.

The previous prime is 1256645659. The next prime is 1256645681. The reversal of 1256645666 is 6665466521.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1256645666.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37040 + ... + 62331.

It is an arithmetic number, because the mean of its divisors is an integer number (235660698).

Almost surely, 2^1256645666 is an apocalyptic number.

1256645666 is a deficient number, since it is larger than the sum of its proper divisors (628639918).

1256645666 is an equidigital number, since it uses as much as digits as its factorization.

1256645666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105696.

The product of its digits is 1555200, while the sum is 47.

The square root of 1256645666 is about 35449.1983830382. The cubic root of 1256645666 is about 1079.1229922990.

The spelling of 1256645666 in words is "one billion, two hundred fifty-six million, six hundred forty-five thousand, six hundred sixty-six".