2256720987 has 6 divisors (see below), whose sum is σ = 3009071028. Its totient is φ = 1504425804.

The previous prime is 2256720979. The next prime is 2256721009. The reversal of 2256720987 is 7890276522.

It is not a de Polignac number, because 2256720987 - 2³ = 2256720979 is a prime.

It is a super-2 number, since 2×2256720987² = 10185579226332508338, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2256720937) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 68568 + ... + 95994.

It is an arithmetic number, because the mean of its divisors is an integer number (501511838).

Almost surely, 2^2256720987 is an apocalyptic number.

2256720987 is a deficient number, since it is larger than the sum of its proper divisors (752350041).

2256720987 is an frugal number, since it uses more digits than its factorization.

2256720987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54857 (or 27430 counting only the distinct ones).

The product of its (nonzero) digits is 846720, while the sum is 48.

The square root of 2256720987 is about 47504.9574991916. The cubic root of 2256720987 is about 1311.6741385584.

Multiplying 2256720987 by its sum of digits (48), we get a square (108322607376 = 329124²).

The spelling of 2256720987 in words is "two billion, two hundred fifty-six million, seven hundred twenty thousand, nine hundred eighty-seven".