639741 has 4 divisors (see below), whose sum is σ = 852992. Its totient is φ = 426492.

The previous prime is 639739. The next prime is 639757. The reversal of 639741 is 147936.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 639741 - 2¹ = 639739 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 639699 and 639708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106621 + ... + 106626.

It is an arithmetic number, because the mean of its divisors is an integer number (213248).

2⁶³⁹⁷⁴¹ is an apocalyptic number.

It is an amenable number.

639741 is a deficient number, since it is larger than the sum of its proper divisors (213251).

639741 is a wasteful number, since it uses less digits than its factorization.

639741 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213250.

The product of its digits is 4536, while the sum is 30.

The square root of 639741 is about 799.8381086195. The cubic root of 639741 is about 86.1657610622.

The spelling of 639741 in words is "six hundred thirty-nine thousand, seven hundred forty-one".