891631 has 8 divisors (see below), whose sum is σ = 970704. Its totient is φ = 814080.

The previous prime is 891629. The next prime is 891643. The reversal of 891631 is 136198.

It is a happy number.

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 891631 - 2¹ = 891629 is a prime.

It is a super-2 number, since 2×891631² = 1590011680322, which contains 22 as substring.

891631 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 891631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (891601) 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, 1071 + ... + 1711.

It is an arithmetic number, because the mean of its divisors is an integer number (121338).

2⁸⁹¹⁶³¹ is an apocalyptic number.

891631 is a deficient number, since it is larger than the sum of its proper divisors (79073).

891631 is a wasteful number, since it uses less digits than its factorization.

891631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 761.

The product of its digits is 1296, while the sum is 28.

The square root of 891631 is about 944.2621458049. The cubic root of 891631 is about 96.2487400746.

It can be divided in two parts, 8916 and 31, that multiplied together give a triangular number (276396 = T₇₄₃).

The spelling of 891631 in words is "eight hundred ninety-one thousand, six hundred thirty-one".