256919121 has 40 divisors (see below), whose sum is σ = 407237600. Its totient is φ = 160963200.

The previous prime is 256919119. The next prime is 256919137. The reversal of 256919121 is 121919652.

256919121 is a `hidden beast` number, since 2 + 569 + 1 + 91 + 2 + 1 = 666.

It is not a de Polignac number, because 256919121 - 2¹ = 256919119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256919021) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 213321 + ... + 214521.

It is an arithmetic number, because the mean of its divisors is an integer number (10180940).

Almost surely, 2^256919121 is an apocalyptic number.

It is an amenable number.

256919121 is a deficient number, since it is larger than the sum of its proper divisors (150318479).

256919121 is a wasteful number, since it uses less digits than its factorization.

256919121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1371 (or 1362 counting only the distinct ones).

The product of its digits is 9720, while the sum is 36.

The square root of 256919121 is about 16028.6967966831. The cubic root of 256919121 is about 635.7194161049.

Adding to 256919121 its product of digits (9720), we get a square (256928841 = 16029²).

The spelling of 256919121 in words is "two hundred fifty-six million, nine hundred nineteen thousand, one hundred twenty-one".