90020813 has 4 divisors (see below), whose sum is σ = 90048288. Its totient is φ = 89993340.

The previous prime is 90020809. The next prime is 90020837. The reversal of 90020813 is 31802009.

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: 31802009 = 29 ⋅1096621.

It is a cyclic number.

It is not a de Polignac number, because 90020813 - 2² = 90020809 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 (90026813) 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 in 3 ways as a sum of consecutive naturals, for example, 8033 + ... + 15638.

It is an arithmetic number, because the mean of its divisors is an integer number (22512072).

Almost surely, 2^90020813 is an apocalyptic number.

It is an amenable number.

90020813 is a deficient number, since it is larger than the sum of its proper divisors (27475).

90020813 is a wasteful number, since it uses less digits than its factorization.

90020813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27474.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 90020813 is about 9487.9298585097. The cubic root of 90020813 is about 448.1750169846.

The spelling of 90020813 in words is "ninety million, twenty thousand, eight hundred thirteen".