99997531 has 2 divisors, whose sum is σ = 99997532. Its totient is φ = 99997530.

The previous prime is 99997523. The next prime is 99997543. The reversal of 99997531 is 13579999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 99997531 - 2³ = 99997523 is a prime.

It is a super-2 number, since 2×99997531² = 19999012412191922, which contains 22 as substring.

It is a nialpdrome in base 10.

It is not a weakly prime, because it can be changed into another prime (99997511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49998765 + 49998766.

It is an arithmetic number, because the mean of its divisors is an integer number (49998766).

Almost surely, 2^99997531 is an apocalyptic number.

99997531 is a deficient number, since it is larger than the sum of its proper divisors (1).

99997531 is an equidigital number, since it uses as much as digits as its factorization.

99997531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 688905, while the sum is 52.

The square root of 99997531 is about 9999.8765492380. The cubic root of 99997531 is about 464.1550633022.

The spelling of 99997531 in words is "ninety-nine million, nine hundred ninety-seven thousand, five hundred thirty-one".