189767981 has 4 divisors (see below), whose sum is σ = 204365532. Its totient is φ = 175170432.

The previous prime is 189767971. The next prime is 189767989.

189767981 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 33292900 + 156475081 = 5770^2 + 12509^2 .

It is a cyclic number.

It is not a de Polignac number, because 189767981 - 2²² = 185573677 is a prime.

It is a super-2 number, since 2×189767981² = 72023773225632722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189767989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7298756 + ... + 7298781.

It is an arithmetic number, because the mean of its divisors is an integer number (51091383).

Almost surely, 2^189767981 is an apocalyptic number.

It is an amenable number.

189767981 is a deficient number, since it is larger than the sum of its proper divisors (14597551).

189767981 is a wasteful number, since it uses less digits than its factorization.

189767981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14597550.

The product of its digits is 1524096, while the sum is 56.

The square root of 189767981 is about 13775.6299674461. The cubic root of 189767981 is about 574.6556032162.

The spelling of 189767981 in words is "one hundred eighty-nine million, seven hundred sixty-seven thousand, nine hundred eighty-one".