644434362433420 has 96 divisors (see below), whose sum is σ = 1479319056250560. Its totient is φ = 234377078722560.

The previous prime is 644434362433417. The next prime is 644434362433423. The reversal of 644434362433420 is 24334263434446.

It is an interprime number because it is at equal distance from previous prime (644434362433417) and next prime (644434362433423).

It is a Harshad number since it is a multiple of its sum of digits (52).

It is not an unprimeable number, because it can be changed into a prime (644434362433423) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7864590 + ... + 36752149.

It is an arithmetic number, because the mean of its divisors is an integer number (15409573502610).

Almost surely, 2^{644434362433420} is an apocalyptic number.

It is an amenable number.

644434362433420 is an abundant number, since it is smaller than the sum of its proper divisors (834884693817140).

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

644434362433420 is a wasteful number, since it uses less digits than its factorization.

644434362433420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44617595 (or 44617593 counting only the distinct ones).

The product of its (nonzero) digits is 47775744, while the sum is 52.

The spelling of 644434362433420 in words is "six hundred forty-four trillion, four hundred thirty-four billion, three hundred sixty-two million, four hundred thirty-three thousand, four hundred twenty".