643634395580 has 48 divisors (see below), whose sum is σ = 1489709049696. Its totient is φ = 231635988480.

The previous prime is 643634395577. The next prime is 643634395589. The reversal of 643634395580 is 85593436346.

It is a happy number.

It is a Smith number, since the sum of its digits (56) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643634395589) 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, 15059129 + ... + 15101808.

It is an arithmetic number, because the mean of its divisors is an integer number (31035605202).

Almost surely, 2^643634395580 is an apocalyptic number.

It is an amenable number.

643634395580 is an abundant number, since it is smaller than the sum of its proper divisors (846074654116).

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

643634395580 is a wasteful number, since it uses less digits than its factorization.

643634395580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30161054 (or 30161052 counting only the distinct ones).

The product of its (nonzero) digits is 27993600, while the sum is 56.

The spelling of 643634395580 in words is "six hundred forty-three billion, six hundred thirty-four million, three hundred ninety-five thousand, five hundred eighty".