21712221191 has 16 divisors (see below), whose sum is σ = 23530521600. Its totient is φ = 19981761888.

The previous prime is 21712221173. The next prime is 21712221199. The reversal of 21712221191 is 19112221712.

It is not a de Polignac number, because 21712221191 - 2³⁴ = 4532352007 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21712221199) 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, 106436 + ... + 233993.

It is an arithmetic number, because the mean of its divisors is an integer number (1470657600).

Almost surely, 2^21712221191 is an apocalyptic number.

21712221191 is a deficient number, since it is larger than the sum of its proper divisors (1818300409).

21712221191 is a wasteful number, since it uses less digits than its factorization.

21712221191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340558.

The product of its digits is 1008, while the sum is 29.

The spelling of 21712221191 in words is "twenty-one billion, seven hundred twelve million, two hundred twenty-one thousand, one hundred ninety-one".