199997531 has 2 divisors, whose sum is σ = 199997532. Its totient is φ = 199997530.

The previous prime is 199997521. The next prime is 199997573. The reversal of 199997531 is 135799991.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 199997531 - 2¹⁴ = 199981147 is a prime.

It is a super-2 number, since 2×199997531² = 79998024812191922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (199997521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99998765 + 99998766.

It is an arithmetic number, because the mean of its divisors is an integer number (99998766).

Almost surely, 2^199997531 is an apocalyptic number.

199997531 is a deficient number, since it is larger than the sum of its proper divisors (1).

199997531 is an equidigital number, since it uses as much as digits as its factorization.

199997531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 688905, while the sum is 53.

The square root of 199997531 is about 14142.0483311294. The cubic root of 199997531 is about 584.8011411661.

The spelling of 199997531 in words is "one hundred ninety-nine million, nine hundred ninety-seven thousand, five hundred thirty-one".