2561157840 has 80 divisors (see below), whose sum is σ = 8108552448. Its totient is φ = 668441088.

The previous prime is 2561157811. The next prime is 2561157883. The reversal of 2561157840 is 487511652.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 102247 + ... + 124806.

Almost surely, 2^2561157840 is an apocalyptic number.

2561157840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2561157840 is an abundant number, since it is smaller than the sum of its proper divisors (5547394608).

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

2561157840 is a wasteful number, since it uses less digits than its factorization.

2561157840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227116 (or 227110 counting only the distinct ones).

The product of its (nonzero) digits is 67200, while the sum is 39.

The square root of 2561157840 is about 50607.8831803900. The cubic root of 2561157840 is about 1368.1869636057.

The spelling of 2561157840 in words is "two billion, five hundred sixty-one million, one hundred fifty-seven thousand, eight hundred forty".