20861716387 has 8 divisors (see below), whose sum is σ = 21962385360. Its totient is φ = 19761315840.

The previous prime is 20861716303. The next prime is 20861716397. The reversal of 20861716387 is 78361716802.

It is a happy number.

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-20861716387 is a prime.

It is a super-2 number, since 2×20861716387² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20861716387.

It is not an unprimeable number, because it can be changed into a prime (20861716397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 103587 + ... + 229027.

It is an arithmetic number, because the mean of its divisors is an integer number (2745298170).

Almost surely, 2^20861716387 is an apocalyptic number.

20861716387 is a deficient number, since it is larger than the sum of its proper divisors (1100668973).

20861716387 is a wasteful number, since it uses less digits than its factorization.

20861716387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134213.

The product of its (nonzero) digits is 677376, while the sum is 49.

The spelling of 20861716387 in words is "twenty billion, eight hundred sixty-one million, seven hundred sixteen thousand, three hundred eighty-seven".