256997966 has 4 divisors (see below), whose sum is σ = 385496952. Its totient is φ = 128498982.

The previous prime is 256997957. The next prime is 256997969. The reversal of 256997966 is 669799652.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256997969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64249490 + ... + 64249493.

It is an arithmetic number, because the mean of its divisors is an integer number (96374238).

Almost surely, 2^256997966 is an apocalyptic number.

256997966 is a deficient number, since it is larger than the sum of its proper divisors (128498986).

256997966 is a wasteful number, since it uses less digits than its factorization.

256997966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128498985.

The product of its digits is 11022480, while the sum is 59.

The square root of 256997966 is about 16031.1561030389. The cubic root of 256997966 is about 635.7844406811.

The spelling of 256997966 in words is "two hundred fifty-six million, nine hundred ninety-seven thousand, nine hundred sixty-six".