2521661557 has 16 divisors (see below), whose sum is σ = 2691151488. Its totient is φ = 2357752320.

The previous prime is 2521661543. The next prime is 2521661579. The reversal of 2521661557 is 7551661252.

It is a cyclic number.

It is not a de Polignac number, because 2521661557 - 2²⁷ = 2387443829 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2521661537) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 183082 + ... + 196372.

It is an arithmetic number, because the mean of its divisors is an integer number (168196968).

Almost surely, 2^2521661557 is an apocalyptic number.

It is an amenable number.

2521661557 is a deficient number, since it is larger than the sum of its proper divisors (169489931).

2521661557 is a wasteful number, since it uses less digits than its factorization.

2521661557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13500.

The product of its digits is 126000, while the sum is 40.

The square root of 2521661557 is about 50216.1483688265. The cubic root of 2521661557 is about 1361.1174417903.

The spelling of 2521661557 in words is "two billion, five hundred twenty-one million, six hundred sixty-one thousand, five hundred fifty-seven".