639964143 has 24 divisors (see below), whose sum is σ = 1137715488. Its totient is φ = 337563072.

The previous prime is 639964097. The next prime is 639964147. The reversal of 639964143 is 341469936.

639964143 is a `hidden beast` number, since 639 + 9 + 6 + 4 + 1 + 4 + 3 = 666.

It is not a de Polignac number, because 639964143 - 2¹⁰ = 639963119 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639964147) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 389880 + ... + 391517.

It is an arithmetic number, because the mean of its divisors is an integer number (47404812).

Almost surely, 2^639964143 is an apocalyptic number.

639964143 is a gapful number since it is divisible by the number (63) formed by its first and last digit.

639964143 is a deficient number, since it is larger than the sum of its proper divisors (497751345).

639964143 is a wasteful number, since it uses less digits than its factorization.

639964143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 781423 (or 781420 counting only the distinct ones).

The product of its digits is 419904, while the sum is 45.

The square root of 639964143 is about 25297.5125852326. The cubic root of 639964143 is about 861.7577816362.

The spelling of 639964143 in words is "six hundred thirty-nine million, nine hundred sixty-four thousand, one hundred forty-three".