21322231391 has 4 divisors (see below), whose sum is σ = 21324137784. Its totient is φ = 21320325000.

The previous prime is 21322231367. The next prime is 21322231451. The reversal of 21322231391 is 19313222312.

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 21322231391 - 2¹⁸ = 21321969247 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 (21322239391) 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, 936320 + ... + 958821.

It is an arithmetic number, because the mean of its divisors is an integer number (5331034446).

Almost surely, 2^21322231391 is an apocalyptic number.

21322231391 is a deficient number, since it is larger than the sum of its proper divisors (1906393).

21322231391 is a wasteful number, since it uses less digits than its factorization.

21322231391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1906392.

The product of its digits is 3888, while the sum is 29.

The spelling of 21322231391 in words is "twenty-one billion, three hundred twenty-two million, two hundred thirty-one thousand, three hundred ninety-one".