21380681871 has 6 divisors (see below), whose sum is σ = 30883207160. Its totient is φ = 14253787908.

The previous prime is 21380681851. The next prime is 21380681887. The reversal of 21380681871 is 17818608312.

It is a happy number.

It is not a de Polignac number, because 21380681871 - 2⁶ = 21380681807 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 (21380681821) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1187815651 + ... + 1187815668.

Almost surely, 2^21380681871 is an apocalyptic number.

21380681871 is a deficient number, since it is larger than the sum of its proper divisors (9502525289).

21380681871 is a wasteful number, since it uses less digits than its factorization.

21380681871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2375631325 (or 2375631322 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The spelling of 21380681871 in words is "twenty-one billion, three hundred eighty million, six hundred eighty-one thousand, eight hundred seventy-one".