2561977748520 has 80 divisors (see below), whose sum is σ = 8611091887860. Its totient is φ = 683194065408.

The previous prime is 2561977748513. The next prime is 2561977748521. The reversal of 2561977748520 is 258477791652.

2561977748520 is a `hidden beast` number, since 2 + 5 + 61 + 9 + 7 + 7 + 7 + 48 + 520 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2073133466244 + 488844282276 = 1439838^2 + 699174^2 .

It is not an unprimeable number, because it can be changed into a prime (2561977748521) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 395363697 + ... + 395370176.

Almost surely, 2^{2561977748520} is an apocalyptic number.

2561977748520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2561977748520 is an abundant number, since it is smaller than the sum of its proper divisors (6049114139340).

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

2561977748520 is a wasteful number, since it uses less digits than its factorization.

2561977748520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 790733896 (or 790733883 counting only the distinct ones).

The product of its (nonzero) digits is 59270400, while the sum is 63.

The spelling of 2561977748520 in words is "two trillion, five hundred sixty-one billion, nine hundred seventy-seven million, seven hundred forty-eight thousand, five hundred twenty".