644557342603 has 4 divisors (see below), whose sum is σ = 661977811360. Its totient is φ = 627136873848.

The previous prime is 644557342591. The next prime is 644557342609. The reversal of 644557342603 is 306243755446.

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

It is a cyclic number.

It is not a de Polignac number, because 644557342603 - 2¹⁷ = 644557211531 is a prime.

It is a super-2 number, since 2×644557342603² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644557342609) 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, 8710234323 + ... + 8710234396.

It is an arithmetic number, because the mean of its divisors is an integer number (165494452840).

Almost surely, 2^644557342603 is an apocalyptic number.

644557342603 is a deficient number, since it is larger than the sum of its proper divisors (17420468757).

644557342603 is a wasteful number, since it uses less digits than its factorization.

644557342603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17420468756.

The product of its (nonzero) digits is 7257600, while the sum is 49.

The spelling of 644557342603 in words is "six hundred forty-four billion, five hundred fifty-seven million, three hundred forty-two thousand, six hundred three".