21891490133 has 2 divisors, whose sum is σ = 21891490134. Its totient is φ = 21891490132.

The previous prime is 21891490123. The next prime is 21891490147. The reversal of 21891490133 is 33109419812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21414810244 + 476679889 = 146338^2 + 21833^2 .

It is a cyclic number.

It is not a de Polignac number, because 21891490133 - 2¹⁴ = 21891473749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21891490123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10945745066 + 10945745067.

It is an arithmetic number, because the mean of its divisors is an integer number (10945745067).

Almost surely, 2^21891490133 is an apocalyptic number.

It is an amenable number.

21891490133 is a deficient number, since it is larger than the sum of its proper divisors (1).

21891490133 is an equidigital number, since it uses as much as digits as its factorization.

21891490133 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 41.

The spelling of 21891490133 in words is "twenty-one billion, eight hundred ninety-one million, four hundred ninety thousand, one hundred thirty-three".