644786790 has 32 divisors (see below), whose sum is σ = 1589315040. Its totient is φ = 167295744.

The previous prime is 644786789. The next prime is 644786797. The reversal of 644786790 is 97687446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644786797) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 289335 + ... + 291554.

It is an arithmetic number, because the mean of its divisors is an integer number (49666095).

Almost surely, 2^644786790 is an apocalyptic number.

644786790 is an abundant number, since it is smaller than the sum of its proper divisors (944528250).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644786790 is a wasteful number, since it uses less digits than its factorization.

644786790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 580936.

The product of its (nonzero) digits is 2032128, while the sum is 51.

The square root of 644786790 is about 25392.6522836824. The cubic root of 644786790 is about 863.9170471843.

The spelling of 644786790 in words is "six hundred forty-four million, seven hundred eighty-six thousand, seven hundred ninety".