646402961 has 4 divisors (see below), whose sum is σ = 661435632. Its totient is φ = 631370292.

The previous prime is 646402937. The next prime is 646402963. The reversal of 646402961 is 169204646.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646402961 is a prime.

It is not an unprimeable number, because it can be changed into a prime (646402963) 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, 7516271 + ... + 7516356.

It is an arithmetic number, because the mean of its divisors is an integer number (165358908).

Almost surely, 2^646402961 is an apocalyptic number.

It is an amenable number.

646402961 is a deficient number, since it is larger than the sum of its proper divisors (15032671).

646402961 is a wasteful number, since it uses less digits than its factorization.

646402961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15032670.

The product of its (nonzero) digits is 62208, while the sum is 38.

The square root of 646402961 is about 25424.4559627143. The cubic root of 646402961 is about 864.6382534060.

The spelling of 646402961 in words is "six hundred forty-six million, four hundred two thousand, nine hundred sixty-one".