21791159218 has 8 divisors (see below), whose sum is σ = 32688075420. Its totient is φ = 10895134080.

The previous prime is 21791159209. The next prime is 21791159227. The reversal of 21791159218 is 81295119712.

It is an interprime number because it is at equal distance from previous prime (21791159209) and next prime (21791159227).

It can be written as a sum of positive squares in 2 ways, for example, as 20943010089 + 848149129 = 144717^2 + 29123^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 157843 + ... + 261718.

Almost surely, 2^21791159218 is an apocalyptic number.

21791159218 is a deficient number, since it is larger than the sum of its proper divisors (10896916202).

21791159218 is a wasteful number, since it uses less digits than its factorization.

21791159218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 445532.

The product of its digits is 90720, while the sum is 46.

The spelling of 21791159218 in words is "twenty-one billion, seven hundred ninety-one million, one hundred fifty-nine thousand, two hundred eighteen".