6440664461 has 16 divisors (see below), whose sum is σ = 8126673408. Its totient is φ = 4958228400.

The previous prime is 6440664449. The next prime is 6440664467. The reversal of 6440664461 is 1644660446.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6440664461 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440664467) 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, 497495 + ... + 510276.

It is an arithmetic number, because the mean of its divisors is an integer number (507917088).

Almost surely, 2^6440664461 is an apocalyptic number.

It is an amenable number.

6440664461 is a deficient number, since it is larger than the sum of its proper divisors (1686008947).

6440664461 is a wasteful number, since it uses less digits than its factorization.

6440664461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1007872.

The product of its (nonzero) digits is 331776, while the sum is 41.

The square root of 6440664461 is about 80253.7504481878. The cubic root of 6440664461 is about 1860.5594783785.

The spelling of 6440664461 in words is "six billion, four hundred forty million, six hundred sixty-four thousand, four hundred sixty-one".