646405659389953 has 4 divisors (see below), whose sum is σ = 646405717363668. Its totient is φ = 646405601416240.

The previous prime is 646405659389951. The next prime is 646405659389977. The reversal of 646405659389953 is 359983956504646.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 369044347617729 + 277361311772224 = 19210527^2 + 16654168^2 .

It is a cyclic number.

It is not a de Polignac number, because 646405659389953 - 2¹ = 646405659389951 is a prime.

It is a super-3 number, since 3×646405659389953³ (a number of 45 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646405659389951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6390118 + ... + 36519103.

It is an arithmetic number, because the mean of its divisors is an integer number (161601429340917).

Almost surely, 2^{646405659389953} is an apocalyptic number.

It is an amenable number.

646405659389953 is a deficient number, since it is larger than the sum of its proper divisors (57973715).

646405659389953 is a wasteful number, since it uses less digits than its factorization.

646405659389953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57973714.

The product of its (nonzero) digits is 22674816000, while the sum is 82.

The spelling of 646405659389953 in words is "six hundred forty-six trillion, four hundred five billion, six hundred fifty-nine million, three hundred eighty-nine thousand, nine hundred fifty-three".