189722721 has 8 divisors (see below), whose sum is σ = 256526784. Its totient is φ = 124700240.

The previous prime is 189722711. The next prime is 189722723. The reversal of 189722721 is 127227981.

189722721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 189722721 - 2¹³ = 189714529 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 189722721.

It is not an unprimeable number, because it can be changed into a prime (189722723) 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, 445146 + ... + 445571.

It is an arithmetic number, because the mean of its divisors is an integer number (32065848).

Almost surely, 2^189722721 is an apocalyptic number.

It is an amenable number.

189722721 is a deficient number, since it is larger than the sum of its proper divisors (66804063).

189722721 is an equidigital number, since it uses as much as digits as its factorization.

189722721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 890791.

The product of its digits is 28224, while the sum is 39.

The square root of 189722721 is about 13773.9871133960. The cubic root of 189722721 is about 574.6099141236.

The spelling of 189722721 in words is "one hundred eighty-nine million, seven hundred twenty-two thousand, seven hundred twenty-one".