644342463 has 12 divisors (see below), whose sum is σ = 931193640. Its totient is φ = 429341616.

The previous prime is 644342441. The next prime is 644342473. The reversal of 644342463 is 364243446.

644342463 is a `hidden beast` number, since 644 + 3 + 4 + 2 + 4 + 6 + 3 = 666.

It is not a de Polignac number, because 644342463 - 2¹⁷ = 644211391 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644342473) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1320 + ... + 35922.

It is an arithmetic number, because the mean of its divisors is an integer number (77599470).

Almost surely, 2^644342463 is an apocalyptic number.

644342463 is a deficient number, since it is larger than the sum of its proper divisors (286851177).

644342463 is a wasteful number, since it uses less digits than its factorization.

644342463 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36678 (or 36675 counting only the distinct ones).

The product of its digits is 165888, while the sum is 36.

The square root of 644342463 is about 25383.9016504556. The cubic root of 644342463 is about 863.7185578627.

It can be divided in two parts, 6 and 44342463, that multiplied together give a triangular number (266054778 = T₂₃₀₆₇).

The spelling of 644342463 in words is "six hundred forty-four million, three hundred forty-two thousand, four hundred sixty-three".