6491444661 has 24 divisors (see below), whose sum is σ = 10133535776. Its totient is φ = 3980599200.

The previous prime is 6491444657. The next prime is 6491444689. The reversal of 6491444661 is 1664441946.

6491444661 is a `hidden beast` number, since 6 + 49 + 144 + 466 + 1 = 666.

It is not a de Polignac number, because 6491444661 - 2² = 6491444657 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6491445661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 64915 + ... + 131136.

Almost surely, 2^6491444661 is an apocalyptic number.

It is an amenable number.

6491444661 is a deficient number, since it is larger than the sum of its proper divisors (3642091115).

6491444661 is a wasteful number, since it uses less digits than its factorization.

6491444661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196353 (or 196350 counting only the distinct ones).

The product of its digits is 497664, while the sum is 45.

The square root of 6491444661 is about 80569.5020525757. The cubic root of 6491444661 is about 1865.4364266493.

The spelling of 6491444661 in words is "six billion, four hundred ninety-one million, four hundred forty-four thousand, six hundred sixty-one".