90691818 has 16 divisors (see below), whose sum is σ = 207295680. Its totient is φ = 25911936.

The previous prime is 90691817. The next prime is 90691819. The reversal of 90691818 is 81819609.

It is an interprime number because it is at equal distance from previous prime (90691817) and next prime (90691819).

It is a Harshad number since it is a multiple of its sum of digits (42), and also a Moran number because the ratio is a prime number: 2159329 = 90691818 / (9 + 0 + 6 + 9 + 1 + 8 + 1 + 8).

It is a self number, because there is not a number n which added to its sum of digits gives 90691818.

It is not an unprimeable number, because it can be changed into a prime (90691817) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1079623 + ... + 1079706.

It is an arithmetic number, because the mean of its divisors is an integer number (12955980).

Almost surely, 2^90691818 is an apocalyptic number.

90691818 is an abundant number, since it is smaller than the sum of its proper divisors (116603862).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

90691818 is a wasteful number, since it uses less digits than its factorization.

90691818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2159341.

The product of its (nonzero) digits is 31104, while the sum is 42.

The square root of 90691818 is about 9523.2251889788. The cubic root of 90691818 is about 449.2858103275.

The spelling of 90691818 in words is "ninety million, six hundred ninety-one thousand, eight hundred eighteen".