644235091393020 has 96 divisors (see below), whose sum is σ = 1806094311174720. Its totient is φ = 171583075768320.

The previous prime is 644235091392967. The next prime is 644235091393079. The reversal of 644235091393020 is 20393190532446.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2887164816 + ... + 2887387944.

It is an arithmetic number, because the mean of its divisors is an integer number (18813482408070).

Almost surely, 2^{644235091393020} is an apocalyptic number.

644235091393020 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

644235091393020 is an abundant number, since it is smaller than the sum of its proper divisors (1161859219781700).

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

644235091393020 is a wasteful number, since it uses less digits than its factorization.

644235091393020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 282575 (or 282573 counting only the distinct ones).

The product of its (nonzero) digits is 4199040, while the sum is 51.

The spelling of 644235091393020 in words is "six hundred forty-four trillion, two hundred thirty-five billion, ninety-one million, three hundred ninety-three thousand, twenty".