256403656615 has 8 divisors (see below), whose sum is σ = 308451683088. Its totient is φ = 204611395200.

The previous prime is 256403656547. The next prime is 256403656631. The reversal of 256403656615 is 516656304652.

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

It is a de Polignac number, because none of the positive numbers 2^k-256403656615 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63939057 + ... + 63943066.

It is an arithmetic number, because the mean of its divisors is an integer number (38556460386).

Almost surely, 2^256403656615 is an apocalyptic number.

256403656615 is a deficient number, since it is larger than the sum of its proper divisors (52048026473).

256403656615 is a wasteful number, since it uses less digits than its factorization.

256403656615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127882529.

The product of its (nonzero) digits is 3888000, while the sum is 49.

The spelling of 256403656615 in words is "two hundred fifty-six billion, four hundred three million, six hundred fifty-six thousand, six hundred fifteen".