2521231661 has 16 divisors (see below), whose sum is σ = 2729458368. Its totient is φ = 2315088000.

The previous prime is 2521231639. The next prime is 2521231693. The reversal of 2521231661 is 1661321252.

2521231661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2521231661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2521231621) 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, 3648326 + ... + 3649016.

It is an arithmetic number, because the mean of its divisors is an integer number (170591148).

Almost surely, 2^2521231661 is an apocalyptic number.

It is an amenable number.

2521231661 is a deficient number, since it is larger than the sum of its proper divisors (208226707).

2521231661 is a wasteful number, since it uses less digits than its factorization.

2521231661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1772.

The product of its digits is 4320, while the sum is 29.

The square root of 2521231661 is about 50211.8677306471. The cubic root of 2521231661 is about 1361.0400890627.

The spelling of 2521231661 in words is "two billion, five hundred twenty-one million, two hundred thirty-one thousand, six hundred sixty-one".