189487981 has 2 divisors, whose sum is σ = 189487982. Its totient is φ = 189487980.

The previous prime is 189487957. The next prime is 189488003. The reversal of 189487981 is 189784981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 148962025 + 40525956 = 12205^2 + 6366^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-189487981 is a prime.

It is a super-2 number, since 2×189487981² = 71811389886912722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (189487381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94743990 + 94743991.

It is an arithmetic number, because the mean of its divisors is an integer number (94743991).

Almost surely, 2^189487981 is an apocalyptic number.

It is an amenable number.

189487981 is a deficient number, since it is larger than the sum of its proper divisors (1).

189487981 is an equidigital number, since it uses as much as digits as its factorization.

189487981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1161216, while the sum is 55.

The square root of 189487981 is about 13765.4633412755. The cubic root of 189487981 is about 574.3728319957.

The spelling of 189487981 in words is "one hundred eighty-nine million, four hundred eighty-seven thousand, nine hundred eighty-one".