189121631 has 2 divisors, whose sum is σ = 189121632. Its totient is φ = 189121630.

The previous prime is 189121589. The next prime is 189121633. The reversal of 189121631 is 136121981.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-189121631 is a prime.

It is a super-2 number, since 2×189121631² = 71533982624200322, which contains 22 as substring.

Together with 189121633, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (189121633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94560815 + 94560816.

It is an arithmetic number, because the mean of its divisors is an integer number (94560816).

Almost surely, 2^189121631 is an apocalyptic number.

189121631 is a deficient number, since it is larger than the sum of its proper divisors (1).

189121631 is an equidigital number, since it uses as much as digits as its factorization.

189121631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 32.

The square root of 189121631 is about 13752.1500500831. The cubic root of 189121631 is about 574.0024351696.

The spelling of 189121631 in words is "one hundred eighty-nine million, one hundred twenty-one thousand, six hundred thirty-one".