21426898191 has 4 divisors (see below), whose sum is σ = 28569197592. Its totient is φ = 14284598792.

The previous prime is 21426898069. The next prime is 21426898201. The reversal of 21426898191 is 19189862412.

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 21426898191 - 2¹⁸ = 21426636047 is a prime.

It is a super-2 number, since 2×21426898191² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21426898391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3571149696 + ... + 3571149701.

It is an arithmetic number, because the mean of its divisors is an integer number (7142299398).

Almost surely, 2^21426898191 is an apocalyptic number.

21426898191 is a deficient number, since it is larger than the sum of its proper divisors (7142299401).

21426898191 is an equidigital number, since it uses as much as digits as its factorization.

21426898191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7142299400.

The product of its digits is 497664, while the sum is 51.

The spelling of 21426898191 in words is "twenty-one billion, four hundred twenty-six million, eight hundred ninety-eight thousand, one hundred ninety-one".