961639 has 8 divisors (see below), whose sum is σ = 1163808. Its totient is φ = 775680.

The previous prime is 961637. The next prime is 961643. The reversal of 961639 is 936169.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 961639 - 2¹ = 961637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (961633) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3922 + ... + 4159.

It is an arithmetic number, because the mean of its divisors is an integer number (145476).

2⁹⁶¹⁶³⁹ is an apocalyptic number.

961639 is a deficient number, since it is larger than the sum of its proper divisors (202169).

961639 is a wasteful number, since it uses less digits than its factorization.

961639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8105.

The product of its digits is 8748, while the sum is 34.

The square root of 961639 is about 980.6319391087. The cubic root of 961639 is about 98.7045916317.

It can be divided in two parts, 961 and 639, that added together give a square (1600 = 40²).

The spelling of 961639 in words is "nine hundred sixty-one thousand, six hundred thirty-nine".