644460666064446 has 64 divisors (see below), whose sum is σ = 1609201859051520. Its totient is φ = 167159567940960.

The previous prime is 644460666064373. The next prime is 644460666064463.

644460666064446 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 969721026 + ... + 970385381.

It is an arithmetic number, because the mean of its divisors is an integer number (25143779047680).

Almost surely, 2^{644460666064446} is an apocalyptic number.

644460666064446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

644460666064446 is an abundant number, since it is smaller than the sum of its proper divisors (964741192987074).

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

644460666064446 is a wasteful number, since it uses less digits than its factorization.

644460666064446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1940107149.

The product of its (nonzero) digits is 1146617856, while the sum is 66.

The spelling of 644460666064446 in words is "six hundred forty-four trillion, four hundred sixty billion, six hundred sixty-six million, sixty-four thousand, four hundred forty-six".