256997247 has 16 divisors (see below), whose sum is σ = 370016640. Its totient is φ = 157725792.

The previous prime is 256997243. The next prime is 256997263. The reversal of 256997247 is 742799652.

It is not a de Polignac number, because 256997247 - 2² = 256997243 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 256997247.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256997243) 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, 6088 + ... + 23474.

It is an arithmetic number, because the mean of its divisors is an integer number (23126040).

Almost surely, 2^256997247 is an apocalyptic number.

256997247 is a deficient number, since it is larger than the sum of its proper divisors (113019393).

256997247 is a wasteful number, since it uses less digits than its factorization.

256997247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17782.

The product of its digits is 1905120, while the sum is 51.

The square root of 256997247 is about 16031.1336779406. The cubic root of 256997247 is about 635.7838477718.

The spelling of 256997247 in words is "two hundred fifty-six million, nine hundred ninety-seven thousand, two hundred forty-seven".