256977381 has 16 divisors (see below), whose sum is σ = 363101760. Its totient is φ = 161374080.

The previous prime is 256977373. The next prime is 256977397. The reversal of 256977381 is 183779652.

It is not a de Polignac number, because 256977381 - 2³ = 256977373 is a prime.

It is a super-2 number, since 2×256977381² = 132074748691238322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 256977381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256976381) 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, 32455 + ... + 39588.

It is an arithmetic number, because the mean of its divisors is an integer number (22693860).

Almost surely, 2^256977381 is an apocalyptic number.

It is an amenable number.

256977381 is a deficient number, since it is larger than the sum of its proper divisors (106124379).

256977381 is a wasteful number, since it uses less digits than its factorization.

256977381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72116.

The product of its digits is 635040, while the sum is 48.

The square root of 256977381 is about 16030.5140591311. The cubic root of 256977381 is about 635.7674652262.

The spelling of 256977381 in words is "two hundred fifty-six million, nine hundred seventy-seven thousand, three hundred eighty-one".