91821053690 has 8 divisors (see below), whose sum is σ = 165277896660. Its totient is φ = 36728421472.

The previous prime is 91821053689. The next prime is 91821053711. The reversal of 91821053690 is 9635012819.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 86426004289 + 5395049401 = 293983^2 + 73451^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×91821053690² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4591052675 + ... + 4591052694.

Almost surely, 2^91821053690 is an apocalyptic number.

91821053690 is a deficient number, since it is larger than the sum of its proper divisors (73456842970).

91821053690 is a wasteful number, since it uses less digits than its factorization.

91821053690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9182105376.

The product of its (nonzero) digits is 116640, while the sum is 44.

The spelling of 91821053690 in words is "ninety-one billion, eight hundred twenty-one million, fifty-three thousand, six hundred ninety".