637979 has 4 divisors (see below), whose sum is σ = 639984. Its totient is φ = 635976.

The previous prime is 637939. The next prime is 638023. The reversal of 637979 is 979736.

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

It is a cyclic number.

It is not a de Polignac number, because 637979 - 2⁸ = 637723 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (637909) 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 3 ways as a sum of consecutive naturals, for example, 407 + ... + 1200.

It is an arithmetic number, because the mean of its divisors is an integer number (159996).

2⁶³⁷⁹⁷⁹ is an apocalyptic number.

637979 is a deficient number, since it is larger than the sum of its proper divisors (2005).

637979 is a wasteful number, since it uses less digits than its factorization.

637979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2004.

The product of its digits is 71442, while the sum is 41.

The square root of 637979 is about 798.7358762445. The cubic root of 637979 is about 86.0865812737.

The spelling of 637979 in words is "six hundred thirty-seven thousand, nine hundred seventy-nine".