90178813 has 2 divisors, whose sum is σ = 90178814. Its totient is φ = 90178812.

The previous prime is 90178793. The next prime is 90178819. The reversal of 90178813 is 31887109.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57426084 + 32752729 = 7578^2 + 5723^2 .

It is a cyclic number.

It is not a de Polignac number, because 90178813 - 2¹³ = 90170621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90178819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45089406 + 45089407.

It is an arithmetic number, because the mean of its divisors is an integer number (45089407).

Almost surely, 2^90178813 is an apocalyptic number.

It is an amenable number.

90178813 is a deficient number, since it is larger than the sum of its proper divisors (1).

90178813 is an equidigital number, since it uses as much as digits as its factorization.

90178813 is an evil number, because the sum of its binary digits is even.

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

The square root of 90178813 is about 9496.2525766747. The cubic root of 90178813 is about 448.4370684752.

The spelling of 90178813 in words is "ninety million, one hundred seventy-eight thousand, eight hundred thirteen".