639142155 has 24 divisors (see below), whose sum is σ = 1115827440. Its totient is φ = 338420160.

The previous prime is 639142151. The next prime is 639142157. The reversal of 639142155 is 551241936.

639142155 is a `hidden beast` number, since 639 + 1 + 4 + 2 + 15 + 5 = 666.

It is not a de Polignac number, because 639142155 - 2² = 639142151 is a prime.

It is not an unprimeable number, because it can be changed into a prime (639142151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 44836 + ... + 57345.

It is an arithmetic number, because the mean of its divisors is an integer number (46492810).

Almost surely, 2^639142155 is an apocalyptic number.

639142155 is a deficient number, since it is larger than the sum of its proper divisors (476685285).

639142155 is a wasteful number, since it uses less digits than its factorization.

639142155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102331 (or 102328 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 639142155 is about 25281.2609456095. The cubic root of 639142155 is about 861.3886682223.

The spelling of 639142155 in words is "six hundred thirty-nine million, one hundred forty-two thousand, one hundred fifty-five".