99991820051 has 16 divisors (see below), whose sum is σ = 109439299584. Its totient is φ = 91079344224.

The previous prime is 99991820021. The next prime is 99991820063. The reversal of 99991820051 is 15002819999.

It is a de Polignac number, because none of the positive numbers 2^k-99991820051 is a prime.

It is a super-2 number, since 2×99991820051² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 99991819975 and 99991820002.

It is not an unprimeable number, because it can be changed into a prime (99991820021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1209995 + ... + 1289988.

It is an arithmetic number, because the mean of its divisors is an integer number (6839956224).

Almost surely, 2^99991820051 is an apocalyptic number.

99991820051 is a deficient number, since it is larger than the sum of its proper divisors (9447479533).

99991820051 is a wasteful number, since it uses less digits than its factorization.

99991820051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2500090.

The product of its (nonzero) digits is 524880, while the sum is 53.

The spelling of 99991820051 in words is "ninety-nine billion, nine hundred ninety-one million, eight hundred twenty thousand, fifty-one".