189745921 has 8 divisors (see below), whose sum is σ = 191094120. Its totient is φ = 188403072.

The previous prime is 189745877. The next prime is 189745937. The reversal of 189745921 is 129547981.

It can be written as a sum of positive squares in 4 ways, for example, as 3013696 + 186732225 = 1736^2 + 13665^2 .

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 189745921 - 2⁷ = 189745793 is a prime.

It is a super-2 number, since 2×189745921² = 72007029072276482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (189745021) 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 7 ways as a sum of consecutive naturals, for example, 90675 + ... + 92743.

It is an arithmetic number, because the mean of its divisors is an integer number (23886765).

Almost surely, 2^189745921 is an apocalyptic number.

It is an amenable number.

189745921 is a deficient number, since it is larger than the sum of its proper divisors (1348199).

189745921 is a wasteful number, since it uses less digits than its factorization.

189745921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2675.

The product of its digits is 181440, while the sum is 46.

The square root of 189745921 is about 13774.8292548401. The cubic root of 189745921 is about 574.6333349814.

The spelling of 189745921 in words is "one hundred eighty-nine million, seven hundred forty-five thousand, nine hundred twenty-one".