21493162091 has 2 divisors, whose sum is σ = 21493162092. Its totient is φ = 21493162090.

The previous prime is 21493162069. The next prime is 21493162129. The reversal of 21493162091 is 19026139412.

It is an a-pointer prime, because the next prime (21493162129) can be obtained adding 21493162091 to its sum of digits (38).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21493162091 is a prime.

It is not a weakly prime, because it can be changed into another prime (21493162391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10746581045 + 10746581046.

It is an arithmetic number, because the mean of its divisors is an integer number (10746581046).

Almost surely, 2^21493162091 is an apocalyptic number.

21493162091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21493162091 is an equidigital number, since it uses as much as digits as its factorization.

21493162091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 38.

The spelling of 21493162091 in words is "twenty-one billion, four hundred ninety-three million, one hundred sixty-two thousand, ninety-one".