646356405 has 16 divisors (see below), whose sum is σ = 1095004224. Its totient is φ = 324445440.

The previous prime is 646356401. The next prime is 646356413. The reversal of 646356405 is 504653646.

It is not a de Polignac number, because 646356405 - 2² = 646356401 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646356401) 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, 1267111 + ... + 1267620.

It is an arithmetic number, because the mean of its divisors is an integer number (68437764).

Almost surely, 2^646356405 is an apocalyptic number.

It is an amenable number.

646356405 is a deficient number, since it is larger than the sum of its proper divisors (448647819).

646356405 is a wasteful number, since it uses less digits than its factorization.

646356405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2534756.

The product of its (nonzero) digits is 259200, while the sum is 39.

The square root of 646356405 is about 25423.5403710813. The cubic root of 646356405 is about 864.6174949073.

The spelling of 646356405 in words is "six hundred forty-six million, three hundred fifty-six thousand, four hundred five".