256138464 has 48 divisors (see below), whose sum is σ = 681851520. Its totient is φ = 84174720.

The previous prime is 256138459. The next prime is 256138481. The reversal of 256138464 is 464831652.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11974 + ... + 25605.

It is an arithmetic number, because the mean of its divisors is an integer number (14205240).

Almost surely, 2^256138464 is an apocalyptic number.

256138464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

256138464 is an abundant number, since it is smaller than the sum of its proper divisors (425713056).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256138464 is a wasteful number, since it uses less digits than its factorization.

256138464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37663 (or 37655 counting only the distinct ones).

The product of its digits is 138240, while the sum is 39.

The square root of 256138464 is about 16004.3264150666. The cubic root of 256138464 is about 635.0748782266.

The spelling of 256138464 in words is "two hundred fifty-six million, one hundred thirty-eight thousand, four hundred sixty-four".