723887921 has 4 divisors (see below), whose sum is σ = 724019712. Its totient is φ = 723756132.

The previous prime is 723887917. The next prime is 723887951. The reversal of 723887921 is 129788327.

723887921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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.

It is a cyclic number.

It is not a de Polignac number, because 723887921 - 2² = 723887917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (723887911) 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, 57281 + ... + 68766.

It is an arithmetic number, because the mean of its divisors is an integer number (181004928).

Almost surely, 2^723887921 is an apocalyptic number.

It is an amenable number.

723887921 is a deficient number, since it is larger than the sum of its proper divisors (131791).

723887921 is a wasteful number, since it uses less digits than its factorization.

723887921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131790.

The product of its digits is 338688, while the sum is 47.

The square root of 723887921 is about 26905.1653219229. The cubic root of 723887921 is about 897.8913270874.

It can be divided in two parts, 7238 and 87921, that added together give a palindrome (95159).

The spelling of 723887921 in words is "seven hundred twenty-three million, eight hundred eighty-seven thousand, nine hundred twenty-one".