644540093 has 8 divisors (see below), whose sum is σ = 658627200. Its totient is φ = 630468640.

The previous prime is 644540077. The next prime is 644540101. The reversal of 644540093 is 390045446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644540093 - 2⁴ = 644540077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644540033) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 124313 + ... + 129393.

It is an arithmetic number, because the mean of its divisors is an integer number (82328400).

Almost surely, 2^644540093 is an apocalyptic number.

It is an amenable number.

644540093 is a deficient number, since it is larger than the sum of its proper divisors (14087107).

644540093 is a wasteful number, since it uses less digits than its factorization.

644540093 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7827.

The product of its (nonzero) digits is 51840, while the sum is 35.

The square root of 644540093 is about 25387.7941735788. The cubic root of 644540093 is about 863.8068542059.

The spelling of 644540093 in words is "six hundred forty-four million, five hundred forty thousand, ninety-three".