639954 has 32 divisors (see below), whose sum is σ = 1626240. Its totient is φ = 182736.

The previous prime is 639949. The next prime is 639959. The reversal of 639954 is 459936.

639954 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (639949) and next prime (639959).

It is a super-2 number, since 2×639954² = 819082244232, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (639959) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 469 + ... + 1224.

It is an arithmetic number, because the mean of its divisors is an integer number (50820).

2⁶³⁹⁹⁵⁴ is an apocalyptic number.

639954 is an abundant number, since it is smaller than the sum of its proper divisors (986286).

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

639954 is a wasteful number, since it uses less digits than its factorization.

639954 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1711 (or 1705 counting only the distinct ones).

The product of its digits is 29160, while the sum is 36.

The square root of 639954 is about 799.9712494834. The cubic root of 639954 is about 86.1753228852.

The spelling of 639954 in words is "six hundred thirty-nine thousand, nine hundred fifty-four".