256191992 has 48 divisors (see below), whose sum is σ = 561180960. Its totient is φ = 109326336.

The previous prime is 256191977. The next prime is 256192007. The reversal of 256191992 is 299191652.

It is an interprime number because it is at equal distance from previous prime (256191977) and next prime (256192007).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 99473 + ... + 102015.

It is an arithmetic number, because the mean of its divisors is an integer number (11691270).

Almost surely, 2^256191992 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256191992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (280590480).

256191992 is an abundant number, since it is smaller than the sum of its proper divisors (304988968).

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

256191992 is a wasteful number, since it uses less digits than its factorization.

256191992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2820 (or 2809 counting only the distinct ones).

The product of its digits is 87480, while the sum is 44.

The square root of 256191992 is about 16005.9986255154. The cubic root of 256191992 is about 635.1191146131.

Adding to 256191992 its sum of digits (44), we get a square (256192036 = 16006²).

The spelling of 256191992 in words is "two hundred fifty-six million, one hundred ninety-one thousand, nine hundred ninety-two".