100821118891 has 4 divisors (see below), whose sum is σ = 100823191984. Its totient is φ = 100819045800.

The previous prime is 100821118823. The next prime is 100821118933. The reversal of 100821118891 is 198811128001.

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

It is a cyclic number.

It is not a de Polignac number, because 100821118891 - 2¹⁹ = 100820594603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (100821148891) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 961800 + ... + 1061461.

It is an arithmetic number, because the mean of its divisors is an integer number (25205797996).

Almost surely, 2^100821118891 is an apocalyptic number.

100821118891 is a deficient number, since it is larger than the sum of its proper divisors (2073093).

100821118891 is an equidigital number, since it uses as much as digits as its factorization.

100821118891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2073092.

The product of its (nonzero) digits is 9216, while the sum is 40.

The spelling of 100821118891 in words is "one hundred billion, eight hundred twenty-one million, one hundred eighteen thousand, eight hundred ninety-one".