21816573407 has 2 divisors, whose sum is σ = 21816573408. Its totient is φ = 21816573406.

The previous prime is 21816573397. The next prime is 21816573421. The reversal of 21816573407 is 70437561812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21816573407 - 2⁸ = 21816573151 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21816573437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10908286703 + 10908286704.

It is an arithmetic number, because the mean of its divisors is an integer number (10908286704).

Almost surely, 2^21816573407 is an apocalyptic number.

21816573407 is a deficient number, since it is larger than the sum of its proper divisors (1).

21816573407 is an equidigital number, since it uses as much as digits as its factorization.

21816573407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 282240, while the sum is 44.

The spelling of 21816573407 in words is "twenty-one billion, eight hundred sixteen million, five hundred seventy-three thousand, four hundred seven".