646354957 has 4 divisors (see below), whose sum is σ = 646527420. Its totient is φ = 646182496.

The previous prime is 646354937. The next prime is 646354967. The reversal of 646354957 is 759453646.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 440748036 + 205606921 = 20994^2 + 14339^2 .

It is a cyclic number.

It is not a de Polignac number, because 646354957 - 2¹⁵ = 646322189 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 646354957.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646354937) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80482 + ... + 88147.

It is an arithmetic number, because the mean of its divisors is an integer number (161631855).

Almost surely, 2^646354957 is an apocalyptic number.

It is an amenable number.

646354957 is a deficient number, since it is larger than the sum of its proper divisors (172463).

646354957 is a wasteful number, since it uses less digits than its factorization.

646354957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172462.

The product of its digits is 2721600, while the sum is 49.

The square root of 646354957 is about 25423.5118935209. The cubic root of 646354957 is about 864.6168492537.

The spelling of 646354957 in words is "six hundred forty-six million, three hundred fifty-four thousand, nine hundred fifty-seven".