913721 has 4 divisors (see below), whose sum is σ = 953472. Its totient is φ = 873972.

The previous prime is 913709. The next prime is 913723. The reversal of 913721 is 127319.

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: 127319 = 19 ⋅6701.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-913721 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 39727 = 913721 / (9 + 1 + 3 + 7 + 2 + 1).

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 913721.

It is not an unprimeable number, because it can be changed into a prime (913723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19841 + ... + 19886.

It is an arithmetic number, because the mean of its divisors is an integer number (238368).

2⁹¹³⁷²¹ is an apocalyptic number.

It is an amenable number.

913721 is a deficient number, since it is larger than the sum of its proper divisors (39751).

913721 is a wasteful number, since it uses less digits than its factorization.

913721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39750.

The product of its digits is 378, while the sum is 23.

The square root of 913721 is about 955.8875456873. The cubic root of 913721 is about 97.0371133711.

The spelling of 913721 in words is "nine hundred thirteen thousand, seven hundred twenty-one".