256121990 has 8 divisors (see below), whose sum is σ = 461019600. Its totient is φ = 102448792.

The previous prime is 256121989. The next prime is 256122019. The reversal of 256121990 is 99121652.

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

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 256121990.

It is a congruent number.

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, 12806090 + ... + 12806109.

It is an arithmetic number, because the mean of its divisors is an integer number (57627450).

Almost surely, 2^256121990 is an apocalyptic number.

256121990 is a deficient number, since it is larger than the sum of its proper divisors (204897610).

256121990 is a wasteful number, since it uses less digits than its factorization.

256121990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25612206.

The product of its (nonzero) digits is 9720, while the sum is 35.

The square root of 256121990 is about 16003.8117334590. The cubic root of 256121990 is about 635.0612626119.

The spelling of 256121990 in words is "two hundred fifty-six million, one hundred twenty-one thousand, nine hundred ninety".