256399145 has 4 divisors (see below), whose sum is σ = 307678980. Its totient is φ = 205119312.

The previous prime is 256399133. The next prime is 256399189. The reversal of 256399145 is 541993652.

256399145 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 48664576 + 207734569 = 6976^2 + 14413^2 .

It is a cyclic number.

It is not a de Polignac number, because 256399145 - 2¹² = 256395049 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 256399096 and 256399105.

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, 25639910 + ... + 25639919.

It is an arithmetic number, because the mean of its divisors is an integer number (76919745).

Almost surely, 2^256399145 is an apocalyptic number.

It is an amenable number.

256399145 is a deficient number, since it is larger than the sum of its proper divisors (51279835).

256399145 is an equidigital number, since it uses as much as digits as its factorization.

256399145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51279834.

The product of its digits is 291600, while the sum is 44.

The square root of 256399145 is about 16012.4684230758. The cubic root of 256399145 is about 635.2902510902.

The spelling of 256399145 in words is "two hundred fifty-six million, three hundred ninety-nine thousand, one hundred forty-five".