644357542 has 8 divisors (see below), whose sum is σ = 967534632. Its totient is φ = 321846000.

The previous prime is 644357521. The next prime is 644357543. The reversal of 644357542 is 245753446.

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

It is a junction number, because it is equal to n+sod(n) for n = 644357495 and 644357504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644357543) 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, 163959 + ... + 167842.

It is an arithmetic number, because the mean of its divisors is an integer number (120941829).

Almost surely, 2^644357542 is an apocalyptic number.

644357542 is a deficient number, since it is larger than the sum of its proper divisors (323177090).

644357542 is a wasteful number, since it uses less digits than its factorization.

644357542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332774.

The product of its digits is 403200, while the sum is 40.

The square root of 644357542 is about 25384.1986676751. The cubic root of 644357542 is about 863.7252954343.

The spelling of 644357542 in words is "six hundred forty-four million, three hundred fifty-seven thousand, five hundred forty-two".