21978112867 has 8 divisors (see below), whose sum is σ = 22184127680. Its totient is φ = 21772177920.

The previous prime is 21978112861. The next prime is 21978112883. The reversal of 21978112867 is 76821187912.

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-21978112867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21978112861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 631942 + ... + 665812.

It is an arithmetic number, because the mean of its divisors is an integer number (2773015960).

Almost surely, 2^21978112867 is an apocalyptic number.

21978112867 is a deficient number, since it is larger than the sum of its proper divisors (206014813).

21978112867 is a wasteful number, since it uses less digits than its factorization.

21978112867 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39933.

The product of its digits is 677376, while the sum is 52.

The spelling of 21978112867 in words is "twenty-one billion, nine hundred seventy-eight million, one hundred twelve thousand, eight hundred sixty-seven".