189707981 has 6 divisors (see below), whose sum is σ = 201524010. Its totient is φ = 178548416.

The previous prime is 189707977. The next prime is 189707983.

189707981 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 3 ways, for example, as 123432100 + 66275881 = 11110^2 + 8141^2 .

It is not a de Polignac number, because 189707981 - 2² = 189707977 is a prime.

It is a super-2 number, since 2×189707981² = 71978236110192722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189707983) 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 in 5 ways as a sum of consecutive naturals, for example, 327926 + ... + 328503.

It is an arithmetic number, because the mean of its divisors is an integer number (33587335).

Almost surely, 2^189707981 is an apocalyptic number.

It is an amenable number.

189707981 is a deficient number, since it is larger than the sum of its proper divisors (11816029).

189707981 is an equidigital number, since it uses as much as digits as its factorization.

189707981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 656463 (or 656446 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 50.

The square root of 189707981 is about 13773.4520364359. The cubic root of 189707981 is about 574.5950328107.

The spelling of 189707981 in words is "one hundred eighty-nine million, seven hundred seven thousand, nine hundred eighty-one".