21493031197 has 18 divisors (see below), whose sum is σ = 24411369822. Its totient is φ = 18908722800.

The previous prime is 21493031171. The next prime is 21493031207. The reversal of 21493031197 is 79113039412.

It can be written as a sum of positive squares in only one way, i.e., 11981710521 + 9511320676 = 109461^2 + 97526^2 .

It is not a de Polignac number, because 21493031197 - 2⁷ = 21493031069 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 (21493031107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 23863 + ... + 208699.

Almost surely, 2^21493031197 is an apocalyptic number.

It is an amenable number.

21493031197 is a deficient number, since it is larger than the sum of its proper divisors (2918338625).

21493031197 is a wasteful number, since it uses less digits than its factorization.

21493031197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184921 (or 184879 counting only the distinct ones).

The product of its (nonzero) digits is 40824, while the sum is 40.

The spelling of 21493031197 in words is "twenty-one billion, four hundred ninety-three million, thirty-one thousand, one hundred ninety-seven".