21998974391 has 8 divisors (see below), whose sum is σ = 22563424800. Its totient is φ = 21435852160.

The previous prime is 21998974363. The next prime is 21998974409. The reversal of 21998974391 is 19347989912.

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

It is a cyclic number.

It is not a de Polignac number, because 21998974391 - 2³⁰ = 20925232567 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21998974331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 298451 + ... + 364788.

It is an arithmetic number, because the mean of its divisors is an integer number (2820428100).

Almost surely, 2^21998974391 is an apocalyptic number.

21998974391 is a deficient number, since it is larger than the sum of its proper divisors (564450409).

21998974391 is an equidigital number, since it uses as much as digits as its factorization.

21998974391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 664089.

The product of its digits is 8817984, while the sum is 62.

The spelling of 21998974391 in words is "twenty-one billion, nine hundred ninety-eight million, nine hundred seventy-four thousand, three hundred ninety-one".