90811813 has 2 divisors, whose sum is σ = 90811814. Its totient is φ = 90811812.

The previous prime is 90811793. The next prime is 90811817. The reversal of 90811813 is 31811809.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 85803169 + 5008644 = 9263^2 + 2238^2 .

It is a cyclic number.

It is not a de Polignac number, because 90811813 - 2¹³ = 90803621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90811817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45405906 + 45405907.

It is an arithmetic number, because the mean of its divisors is an integer number (45405907).

Almost surely, 2^90811813 is an apocalyptic number.

It is an amenable number.

90811813 is a deficient number, since it is larger than the sum of its proper divisors (1).

90811813 is an equidigital number, since it uses as much as digits as its factorization.

90811813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 31.

The square root of 90811813 is about 9529.5232304665. The cubic root of 90811813 is about 449.4838741012.

It can be divided in two parts, 908 and 11813, that added together give a palindrome (12721).

The spelling of 90811813 in words is "ninety million, eight hundred eleven thousand, eight hundred thirteen".