2543660991 has 6 divisors (see below), whose sum is σ = 3674177000. Its totient is φ = 1695773988.

The previous prime is 2543660969. The next prime is 2543660993. The reversal of 2543660991 is 1990663452.

2543660991 is a `hidden beast` number, since 2 + 5 + 4 + 36 + 609 + 9 + 1 = 666.

It is not a de Polignac number, because 2543660991 - 2⁶ = 2543660927 is a prime.

It is a super-2 number, since 2×2543660991² = 12940422474270204162, 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 (2543660993) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 141314491 + ... + 141314508.

Almost surely, 2^2543660991 is an apocalyptic number.

2543660991 is a deficient number, since it is larger than the sum of its proper divisors (1130516009).

2543660991 is a wasteful number, since it uses less digits than its factorization.

2543660991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282629005 (or 282629002 counting only the distinct ones).

The product of its (nonzero) digits is 349920, while the sum is 45.

The square root of 2543660991 is about 50434.7200943953. The cubic root of 2543660991 is about 1365.0641985665.

The spelling of 2543660991 in words is "two billion, five hundred forty-three million, six hundred sixty thousand, nine hundred ninety-one".