915661 has 4 divisors (see below), whose sum is σ = 921312. Its totient is φ = 910012.

The previous prime is 915659. The next prime is 915683. The reversal of 915661 is 166519.

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, and also an emirpimes, since its reverse is a distinct semiprime: 166519 = 89 ⋅1871.

It is a cyclic number.

It is not a de Polignac number, because 915661 - 2¹ = 915659 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 (915601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2575 + ... + 2908.

It is an arithmetic number, because the mean of its divisors is an integer number (230328).

2⁹¹⁵⁶⁶¹ is an apocalyptic number.

It is an amenable number.

915661 is a deficient number, since it is larger than the sum of its proper divisors (5651).

915661 is a wasteful number, since it uses less digits than its factorization.

915661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5650.

The product of its digits is 1620, while the sum is 28.

The square root of 915661 is about 956.9017713433. The cubic root of 915661 is about 97.1057407841.

The spelling of 915661 in words is "nine hundred fifteen thousand, six hundred sixty-one".