644665453514 has 4 divisors (see below), whose sum is σ = 966998180274. Its totient is φ = 322332726756.

The previous prime is 644665453513. The next prime is 644665453517. The reversal of 644665453514 is 415354566446.

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

It can be written as a sum of positive squares in only one way, i.e., 526978720489 + 117686733025 = 725933^2 + 343055^2 .

It is a super-2 number, since 2×644665453514² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (644665453513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161166363377 + ... + 161166363380.

Almost surely, 2^644665453514 is an apocalyptic number.

644665453514 is a deficient number, since it is larger than the sum of its proper divisors (322332726760).

644665453514 is a wasteful number, since it uses less digits than its factorization.

644665453514 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322332726759.

The product of its digits is 20736000, while the sum is 53.

The spelling of 644665453514 in words is "six hundred forty-four billion, six hundred sixty-five million, four hundred fifty-three thousand, five hundred fourteen".