646366861 has 32 divisors (see below), whose sum is σ = 790732800. Its totient is φ = 516447360.

The previous prime is 646366849. The next prime is 646366879. The reversal of 646366861 is 168663646.

It is a cyclic number.

It is not a de Polignac number, because 646366861 - 2²⁵ = 612812429 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646366811) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1131706 + ... + 1132276.

It is an arithmetic number, because the mean of its divisors is an integer number (24710400).

Almost surely, 2^646366861 is an apocalyptic number.

It is an amenable number.

646366861 is a deficient number, since it is larger than the sum of its proper divisors (144365939).

646366861 is a wasteful number, since it uses less digits than its factorization.

646366861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 769.

The product of its digits is 746496, while the sum is 46.

The square root of 646366861 is about 25423.7460064405. The cubic root of 646366861 is about 864.6221571400.

The spelling of 646366861 in words is "six hundred forty-six million, three hundred sixty-six thousand, eight hundred sixty-one".