913991 has 8 divisors (see below), whose sum is σ = 992544. Its totient is φ = 836640.

The previous prime is 913981. The next prime is 913999. The reversal of 913991 is 199319.

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 913991 - 2¹⁴ = 897607 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 (913999) 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, 1961 + ... + 2381.

It is an arithmetic number, because the mean of its divisors is an integer number (124068).

2⁹¹³⁹⁹¹ is an apocalyptic number.

913991 is a deficient number, since it is larger than the sum of its proper divisors (78553).

913991 is a wasteful number, since it uses less digits than its factorization.

913991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 601.

The product of its digits is 2187, while the sum is 32.

The square root of 913991 is about 956.0287652576. The cubic root of 913991 is about 97.0466704242.

The spelling of 913991 in words is "nine hundred thirteen thousand, nine hundred ninety-one".