21199707671 has 4 divisors (see below), whose sum is σ = 21201625752. Its totient is φ = 21197789592.

The previous prime is 21199707667. The next prime is 21199707677. The reversal of 21199707671 is 17670799112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21199707671 - 2² = 21199707667 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 (21199707677) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 942365 + ... + 964598.

It is an arithmetic number, because the mean of its divisors is an integer number (5300406438).

Almost surely, 2^21199707671 is an apocalyptic number.

21199707671 is a deficient number, since it is larger than the sum of its proper divisors (1918081).

21199707671 is a wasteful number, since it uses less digits than its factorization.

21199707671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1918080.

The product of its (nonzero) digits is 333396, while the sum is 50.

The spelling of 21199707671 in words is "twenty-one billion, one hundred ninety-nine million, seven hundred seven thousand, six hundred seventy-one".