90999999973 has 2 divisors, whose sum is σ = 90999999974. Its totient is φ = 90999999972.

The previous prime is 90999999953. The next prime is 91000000037. The reversal of 90999999973 is 37999999909.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62884088289 + 28115911684 = 250767^2 + 167678^2 .

It is an emirp because it is prime and its reverse (37999999909) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90999999973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90999999953) 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, 45499999986 + 45499999987.

It is an arithmetic number, because the mean of its divisors is an integer number (45499999987).

Almost surely, 2^90999999973 is an apocalyptic number.

It is an amenable number.

90999999973 is a deficient number, since it is larger than the sum of its proper divisors (1).

90999999973 is an equidigital number, since it uses as much as digits as its factorization.

90999999973 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 903981141, while the sum is 82.

The spelling of 90999999973 in words is "ninety billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred seventy-three".