21678836387 has 8 divisors (see below), whose sum is σ = 23915865120. Its totient is φ = 19523154240.

The previous prime is 21678836383. The next prime is 21678836411. The reversal of 21678836387 is 78363887612.

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 21678836387 - 2² = 21678836383 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21678836383) 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, 20336087 + ... + 20337152.

It is an arithmetic number, because the mean of its divisors is an integer number (2989483140).

Almost surely, 2^21678836387 is an apocalyptic number.

21678836387 is a deficient number, since it is larger than the sum of its proper divisors (2237028733).

21678836387 is a wasteful number, since it uses less digits than its factorization.

21678836387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40673293.

The product of its digits is 16257024, while the sum is 59.

The spelling of 21678836387 in words is "twenty-one billion, six hundred seventy-eight million, eight hundred thirty-six thousand, three hundred eighty-seven".