644066143045511 has 4 divisors (see below), whose sum is σ = 644066238362400. Its totient is φ = 644066047728624.

The previous prime is 644066143045483. The next prime is 644066143045517. The reversal of 644066143045511 is 115540341660446.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644066143045511 is a prime.

It is a super-2 number, since 2×644066143045511² (a number of 30 digits) contains 22 as substring.

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 644066143045511.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644066143045517) 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, 36679766 + ... + 51318003.

It is an arithmetic number, because the mean of its divisors is an integer number (161016559590600).

Almost surely, 2^{644066143045511} is an apocalyptic number.

644066143045511 is a deficient number, since it is larger than the sum of its proper divisors (95316889).

644066143045511 is an equidigital number, since it uses as much as digits as its factorization.

644066143045511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95316888.

The product of its (nonzero) digits is 4147200, while the sum is 50.

The spelling of 644066143045511 in words is "six hundred forty-four trillion, sixty-six billion, one hundred forty-three million, forty-five thousand, five hundred eleven".