21623980091 has 4 divisors (see below), whose sum is σ = 24713120112. Its totient is φ = 18534840072.

The previous prime is 21623980087. The next prime is 21623980099. The reversal of 21623980091 is 19008932612.

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

It is not a de Polignac number, because 21623980091 - 2² = 21623980087 is a prime.

It is a super-3 number, since 3×21623980091³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21623980099) 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, 1544570000 + ... + 1544570013.

It is an arithmetic number, because the mean of its divisors is an integer number (6178280028).

Almost surely, 2^21623980091 is an apocalyptic number.

21623980091 is a deficient number, since it is larger than the sum of its proper divisors (3089140021).

21623980091 is an equidigital number, since it uses as much as digits as its factorization.

21623980091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3089140020.

The product of its (nonzero) digits is 46656, while the sum is 41.

The spelling of 21623980091 in words is "twenty-one billion, six hundred twenty-three million, nine hundred eighty thousand, ninety-one".