2543251661 has 4 divisors (see below), whose sum is σ = 2575444800. Its totient is φ = 2511058524.

The previous prime is 2543251651. The next prime is 2543251729. The reversal of 2543251661 is 1661523452.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2543251661 - 2⁶ = 2543251597 is a prime.

It is a super-2 number, since 2×2543251661² = 12936258022358517842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2543251651) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16096451 + ... + 16096608.

It is an arithmetic number, because the mean of its divisors is an integer number (643861200).

Almost surely, 2^2543251661 is an apocalyptic number.

It is an amenable number.

2543251661 is a deficient number, since it is larger than the sum of its proper divisors (32193139).

2543251661 is an equidigital number, since it uses as much as digits as its factorization.

2543251661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32193138.

The product of its digits is 43200, while the sum is 35.

The square root of 2543251661 is about 50430.6619131655. The cubic root of 2543251661 is about 1364.9909718662.

The spelling of 2543251661 in words is "two billion, five hundred forty-three million, two hundred fifty-one thousand, six hundred sixty-one".