90991501 has 2 divisors, whose sum is σ = 90991502. Its totient is φ = 90991500.

The previous prime is 90991499. The next prime is 90991517. The reversal of 90991501 is 10519909.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 90269001 + 722500 = 9501^2 + 850^2 .

It is an emirp because it is prime and its reverse (10519909) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90991501 - 2¹ = 90991499 is a prime.

Together with 90991499, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90995501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45495750 + 45495751.

It is an arithmetic number, because the mean of its divisors is an integer number (45495751).

Almost surely, 2^90991501 is an apocalyptic number.

It is an amenable number.

90991501 is a deficient number, since it is larger than the sum of its proper divisors (1).

90991501 is an equidigital number, since it uses as much as digits as its factorization.

90991501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3645, while the sum is 34.

The square root of 90991501 is about 9538.9465351264. The cubic root of 90991501 is about 449.7801411596.

The spelling of 90991501 in words is "ninety million, nine hundred ninety-one thousand, five hundred one".