644052545 has 4 divisors (see below), whose sum is σ = 772863060. Its totient is φ = 515242032.

The previous prime is 644052529. The next prime is 644052553. The reversal of 644052545 is 545250446.

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

It can be written as a sum of positive squares in 2 ways, for example, as 199854769 + 444197776 = 14137^2 + 21076^2 .

It is a cyclic number.

It is not a de Polignac number, because 644052545 - 2⁴ = 644052529 is a prime.

It is a super-3 number, since 3×644052545³ (a number of 27 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64405250 + ... + 64405259.

It is an arithmetic number, because the mean of its divisors is an integer number (193215765).

Almost surely, 2^644052545 is an apocalyptic number.

It is an amenable number.

644052545 is a deficient number, since it is larger than the sum of its proper divisors (128810515).

644052545 is a wasteful number, since it uses less digits than its factorization.

644052545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128810514.

The product of its (nonzero) digits is 96000, while the sum is 35.

The square root of 644052545 is about 25378.1903413147. The cubic root of 644052545 is about 863.5889967793.

It can be divided in two parts, 6440 and 52545, that added together give a palindrome (58985).

The spelling of 644052545 in words is "six hundred forty-four million, fifty-two thousand, five hundred forty-five".