91810212004 has 81 divisors (see below), whose sum is σ = 195586575681. Its totient is φ = 37596488160.

The previous prime is 91810211989. The next prime is 91810212029. The reversal of 91810212004 is 40021201819.

The square root of 91810212004 is 303002.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 56930914404 + 34879297600 = 238602^2 + 186760^2 .

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 97566174 + ... + 97567114.

Almost surely, 2^91810212004 is an apocalyptic number.

91810212004 is the 303002-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91810212004

91810212004 is an abundant number, since it is smaller than the sum of its proper divisors (103776363677).

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

91810212004 is an equidigital number, since it uses as much as digits as its factorization.

91810212004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1946 (or 973 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 28.

The spelling of 91810212004 in words is "ninety-one billion, eight hundred ten million, two hundred twelve thousand, four".