16621765615493 has 2 divisors, whose sum is σ = 16621765615494. Its totient is φ = 16621765615492.

The previous prime is 16621765615463. The next prime is 16621765615513. The reversal of 16621765615493 is 39451656712661.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8648410509124 + 7973355106369 = 2940818^2 + 2823713^2 .

It is a cyclic number.

It is not a de Polignac number, because 16621765615493 - 2¹⁰ = 16621765614469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16621765615463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8310882807746 + 8310882807747.

It is an arithmetic number, because the mean of its divisors is an integer number (8310882807747).

Almost surely, 2^{16621765615493} is an apocalyptic number.

It is an amenable number.

16621765615493 is a deficient number, since it is larger than the sum of its proper divisors (1).

16621765615493 is an equidigital number, since it uses as much as digits as its factorization.

16621765615493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48988800, while the sum is 62.

The spelling of 16621765615493 in words is "sixteen trillion, six hundred twenty-one billion, seven hundred sixty-five million, six hundred fifteen thousand, four hundred ninety-three".