644534132670 has 96 divisors (see below), whose sum is σ = 1774537670880. Its totient is φ = 161749647360.

The previous prime is 644534132633. The next prime is 644534132677. The reversal of 644534132670 is 76231435446.

644534132670 is a `hidden beast` number, since 6 + 4 + 45 + 341 + 3 + 267 + 0 = 666.

It is a super-2 number, since 2×644534132670² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644534132677) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 29871646 + ... + 29893214.

It is an arithmetic number, because the mean of its divisors is an integer number (18484767405).

Almost surely, 2^644534132670 is an apocalyptic number.

644534132670 is an abundant number, since it is smaller than the sum of its proper divisors (1130003538210).

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

644534132670 is a wasteful number, since it uses less digits than its factorization.

644534132670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41130 (or 41127 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 45.

The spelling of 644534132670 in words is "six hundred forty-four billion, five hundred thirty-four million, one hundred thirty-two thousand, six hundred seventy".