1989695231 has 2 divisors, whose sum is σ = 1989695232. Its totient is φ = 1989695230.

The previous prime is 1989695221. The next prime is 1989695233. The reversal of 1989695231 is 1325969891.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1989695231 - 2⁶ = 1989695167 is a prime.

It is a super-2 number, since 2×1989695231² = 7917774224528286722, which contains 22 as substring.

Together with 1989695233, 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 (1989695233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994847615 + 994847616.

It is an arithmetic number, because the mean of its divisors is an integer number (994847616).

Almost surely, 2^1989695231 is an apocalyptic number.

1989695231 is a deficient number, since it is larger than the sum of its proper divisors (1).

1989695231 is an equidigital number, since it uses as much as digits as its factorization.

1989695231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1049760, while the sum is 53.

The square root of 1989695231 is about 44605.9999439537. Note that the first 4 decimals coincide. The cubic root of 1989695231 is about 1257.7534569678.

The spelling of 1989695231 in words is "one billion, nine hundred eighty-nine million, six hundred ninety-five thousand, two hundred thirty-one".