644586685446 has 32 divisors (see below), whose sum is σ = 1415328749568. Its totient is φ = 194085159840.

The previous prime is 644586685441. The next prime is 644586685487.

It is a happy number.

644586685446 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 not an unprimeable number, because it can be changed into a prime (644586685441) 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, 31093030 + ... + 31113753.

It is an arithmetic number, because the mean of its divisors is an integer number (44229023424).

Almost surely, 2^644586685446 is an apocalyptic number.

644586685446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

644586685446 is an abundant number, since it is smaller than the sum of its proper divisors (770742064122).

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

644586685446 is a wasteful number, since it uses less digits than its factorization.

644586685446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62206956.

The product of its digits is 530841600, while the sum is 66.

The spelling of 644586685446 in words is "six hundred forty-four billion, five hundred eighty-six million, six hundred eighty-five thousand, four hundred forty-six".