90691819 has 2 divisors, whose sum is σ = 90691820. Its totient is φ = 90691818.

The previous prime is 90691817. The next prime is 90691823. The reversal of 90691819 is 91819609.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 90691819 - 2¹ = 90691817 is a prime.

It is a super-2 number, since 2×90691819² = 16450012067057522, which contains 22 as substring.

Together with 90691817, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (90691817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45345909 + 45345910.

It is an arithmetic number, because the mean of its divisors is an integer number (45345910).

Almost surely, 2^90691819 is an apocalyptic number.

90691819 is a deficient number, since it is larger than the sum of its proper divisors (1).

90691819 is an equidigital number, since it uses as much as digits as its factorization.

90691819 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 43.

The square root of 90691819 is about 9523.2252414820. The cubic root of 90691819 is about 449.2858119789.

The spelling of 90691819 in words is "ninety million, six hundred ninety-one thousand, eight hundred nineteen".