90817813 has 4 divisors (see below), whose sum is σ = 91139008. Its totient is φ = 90496620.

The previous prime is 90817807. The next prime is 90817841. The reversal of 90817813 is 31871809.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31871809 = 983 ⋅32423.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90817813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90817843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 160173 + ... + 160738.

It is an arithmetic number, because the mean of its divisors is an integer number (22784752).

Almost surely, 2^90817813 is an apocalyptic number.

It is an amenable number.

90817813 is a deficient number, since it is larger than the sum of its proper divisors (321195).

90817813 is a wasteful number, since it uses less digits than its factorization.

90817813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321194.

The product of its (nonzero) digits is 12096, while the sum is 37.

The square root of 90817813 is about 9529.8380363991. The cubic root of 90817813 is about 449.4937731211.

It can be divided in two parts, 908 and 17813, that added together give a triangular number (18721 = T₁₉₃).

The spelling of 90817813 in words is "ninety million, eight hundred seventeen thousand, eight hundred thirteen".