21890124517 has 2 divisors, whose sum is σ = 21890124518. Its totient is φ = 21890124516.

The previous prime is 21890124493. The next prime is 21890124533. The reversal of 21890124517 is 71542109812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16157968996 + 5732155521 = 127114^2 + 75711^2 .

It is a cyclic number.

It is not a de Polignac number, because 21890124517 - 2¹¹ = 21890122469 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21890124517.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21890124577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10945062258 + 10945062259.

It is an arithmetic number, because the mean of its divisors is an integer number (10945062259).

Almost surely, 2^21890124517 is an apocalyptic number.

It is an amenable number.

21890124517 is a deficient number, since it is larger than the sum of its proper divisors (1).

21890124517 is an equidigital number, since it uses as much as digits as its factorization.

21890124517 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40320, while the sum is 40.

The spelling of 21890124517 in words is "twenty-one billion, eight hundred ninety million, one hundred twenty-four thousand, five hundred seventeen".