189897251 has 4 divisors (see below), whose sum is σ = 193480272. Its totient is φ = 186314232.

The previous prime is 189897241. The next prime is 189897263. The reversal of 189897251 is 152798981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 152798981 = 733 ⋅208457.

It is a cyclic number.

It is not a de Polignac number, because 189897251 - 2⁶ = 189897187 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 189897251.

It is not an unprimeable number, because it can be changed into a prime (189897221) 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 3 ways as a sum of consecutive naturals, for example, 1791431 + ... + 1791536.

It is an arithmetic number, because the mean of its divisors is an integer number (48370068).

Almost surely, 2^189897251 is an apocalyptic number.

189897251 is a deficient number, since it is larger than the sum of its proper divisors (3583021).

189897251 is an equidigital number, since it uses as much as digits as its factorization.

189897251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3583020.

The product of its digits is 362880, while the sum is 50.

The square root of 189897251 is about 13780.3211501039. The cubic root of 189897251 is about 574.7860587827.

The spelling of 189897251 in words is "one hundred eighty-nine million, eight hundred ninety-seven thousand, two hundred fifty-one".