639823545 has 48 divisors (see below), whose sum is σ = 1160490240. Its totient is φ = 325488768.

The previous prime is 639823523. The next prime is 639823603. The reversal of 639823545 is 545328936.

639823545 is a `hidden beast` number, since 639 + 8 + 2 + 3 + 5 + 4 + 5 = 666.

It is not a de Polignac number, because 639823545 - 2⁷ = 639823417 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 639823545.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 519991 + ... + 521219.

It is an arithmetic number, because the mean of its divisors is an integer number (24176880).

Almost surely, 2^639823545 is an apocalyptic number.

It is an amenable number.

639823545 is a deficient number, since it is larger than the sum of its proper divisors (520666695).

639823545 is a wasteful number, since it uses less digits than its factorization.

639823545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1766 (or 1763 counting only the distinct ones).

The product of its digits is 777600, while the sum is 45.

The square root of 639823545 is about 25294.7335427753. The cubic root of 639823545 is about 861.6946685718.

The spelling of 639823545 in words is "six hundred thirty-nine million, eight hundred twenty-three thousand, five hundred forty-five".