189915961 has 3 divisors (see below), whose sum is σ = 189929743. Its totient is φ = 189902180.

The previous prime is 189915949. The next prime is 189916007. The reversal of 189915961 is 169519981.

The square root of 189915961 is 13781.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 108555561 + 81360400 = 10419^2 + 9020^2 .

It is not a de Polignac number, because 189915961 - 2⁷ = 189915833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (189915911) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 6891 + ... + 20671.

Almost surely, 2^189915961 is an apocalyptic number.

189915961 is the 13781-st square number.

189915961 is the 6891-st centered octagonal number.

It is an amenable number.

189915961 is a deficient number, since it is larger than the sum of its proper divisors (13782).

189915961 is an frugal number, since it uses more digits than its factorization.

189915961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27562 (or 13781 counting only the distinct ones).

The product of its digits is 174960, while the sum is 49.

The cubic root of 189915961 is about 574.8049354716.

Multiplying 189915961 by its sum of digits (49), we get a square (9305882089 = 96467²).

The spelling of 189915961 in words is "one hundred eighty-nine million, nine hundred fifteen thousand, nine hundred sixty-one".