644254066423206 has 64 divisors (see below), whose sum is σ = 1435522041676800. Its totient is φ = 214174711463328.

The previous prime is 644254066423133. The next prime is 644254066423243. The reversal of 644254066423206 is 602324660452446.

644254066423206 is a `hidden beast` number, since 6 + 4 + 4 + 2 + 5 + 4 + 0 + 6 + 6 + 423 + 206 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 71379960 + ... + 79897476.

It is an arithmetic number, because the mean of its divisors is an integer number (22430031901200).

Almost surely, 2^{644254066423206} is an apocalyptic number.

644254066423206 is an abundant number, since it is smaller than the sum of its proper divisors (791267975253594).

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

644254066423206 is a wasteful number, since it uses less digits than its factorization.

644254066423206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8521290 (or 8521284 counting only the distinct ones).

The product of its (nonzero) digits is 39813120, while the sum is 54.

The spelling of 644254066423206 in words is "six hundred forty-four trillion, two hundred fifty-four billion, sixty-six million, four hundred twenty-three thousand, two hundred six".