21613454891 has 8 divisors (see below), whose sum is σ = 24705483264. Its totient is φ = 18522524520.

The previous prime is 21613454881. The next prime is 21613454899. The reversal of 21613454891 is 19845431612.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21613454891 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21613454899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 231875 + ... + 311436.

It is an arithmetic number, because the mean of its divisors is an integer number (3088185408).

Almost surely, 2^21613454891 is an apocalyptic number.

21613454891 is a deficient number, since it is larger than the sum of its proper divisors (3092028373).

21613454891 is an equidigital number, since it uses as much as digits as its factorization.

21613454891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 549001.

The product of its digits is 207360, while the sum is 44.

The spelling of 21613454891 in words is "twenty-one billion, six hundred thirteen million, four hundred fifty-four thousand, eight hundred ninety-one".