639622 has 4 divisors (see below), whose sum is σ = 959436. Its totient is φ = 319810.

The previous prime is 639601. The next prime is 639631. The reversal of 639622 is 226936.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

639622 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159904 + ... + 159907.

It is an arithmetic number, because the mean of its divisors is an integer number (239859).

2⁶³⁹⁶²² is an apocalyptic number.

639622 is a deficient number, since it is larger than the sum of its proper divisors (319814).

639622 is a wasteful number, since it uses less digits than its factorization.

639622 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319813.

The product of its digits is 3888, while the sum is 28.

The square root of 639622 is about 799.7637151059. The cubic root of 639622 is about 86.1604180868.

Subtracting from 639622 its reverse (226936), we obtain a triangular number (412686 = T₉₀₈).

It can be divided in two parts, 6 and 39622, that multiplied together give a palindrome (237732).

The spelling of 639622 in words is "six hundred thirty-nine thousand, six hundred twenty-two".