21231031193 has 2 divisors, whose sum is σ = 21231031194. Its totient is φ = 21231031192.

The previous prime is 21231031187. The next prime is 21231031223. The reversal of 21231031193 is 39113013212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20479613449 + 751417744 = 143107^2 + 27412^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231031193 - 2¹⁰ = 21231030169 is a prime.

It is not a weakly prime, because it can be changed into another prime (21231031793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615515596 + 10615515597.

It is an arithmetic number, because the mean of its divisors is an integer number (10615515597).

Almost surely, 2^21231031193 is an apocalyptic number.

It is an amenable number.

21231031193 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231031193 is an equidigital number, since it uses as much as digits as its factorization.

21231031193 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 26.

The spelling of 21231031193 in words is "twenty-one billion, two hundred thirty-one million, thirty-one thousand, one hundred ninety-three".