21871832187 has 16 divisors (see below), whose sum is σ = 29728995840. Its totient is φ = 14298247392.

The previous prime is 21871832183. The next prime is 21871832249. The reversal of 21871832187 is 78123817812.

It is a happy number.

It is not a de Polignac number, because 21871832187 - 2² = 21871832183 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21871832183) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 260014 + ... + 333692.

It is an arithmetic number, because the mean of its divisors is an integer number (1858062240).

Almost surely, 2^21871832187 is an apocalyptic number.

21871832187 is a deficient number, since it is larger than the sum of its proper divisors (7857163653).

21871832187 is a wasteful number, since it uses less digits than its factorization.

21871832187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75602.

The product of its digits is 301056, while the sum is 48.

The spelling of 21871832187 in words is "twenty-one billion, eight hundred seventy-one million, eight hundred thirty-two thousand, one hundred eighty-seven".