891639 has 12 divisors (see below), whose sum is σ = 1472016. Its totient is φ = 509472.

The previous prime is 891629. The next prime is 891643. The reversal of 891639 is 936198.

It is not a de Polignac number, because 891639 - 2¹² = 887543 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (891629) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7014 + ... + 7139.

It is an arithmetic number, because the mean of its divisors is an integer number (122668).

2⁸⁹¹⁶³⁹ is an apocalyptic number.

891639 is a deficient number, since it is larger than the sum of its proper divisors (580377).

891639 is a wasteful number, since it uses less digits than its factorization.

891639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14166 (or 14163 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 891639 is about 944.2663819071. The cubic root of 891639 is about 96.2490279319.

It can be divided in two parts, 89 and 1639, that added together give a cube (1728 = 12³).

The spelling of 891639 in words is "eight hundred ninety-one thousand, six hundred thirty-nine".