91820818 has 4 divisors (see below), whose sum is σ = 137731230. Its totient is φ = 45910408.

The previous prime is 91820783. The next prime is 91820849. The reversal of 91820818 is 81802819.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 79869969 + 11950849 = 8937^2 + 3457^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22955203 + ... + 22955206.

Almost surely, 2^91820818 is an apocalyptic number.

91820818 is a deficient number, since it is larger than the sum of its proper divisors (45910412).

91820818 is a wasteful number, since it uses less digits than its factorization.

91820818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45910411.

The product of its (nonzero) digits is 9216, while the sum is 37.

The square root of 91820818 is about 9582.3179867921. The cubic root of 91820818 is about 451.1424764084.

It can be divided in two parts, 918 and 20818, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 91820818 in words is "ninety-one million, eight hundred twenty thousand, eight hundred eighteen".