16521864929257 has 2 divisors, whose sum is σ = 16521864929258. Its totient is φ = 16521864929256.

The previous prime is 16521864929233. The next prime is 16521864929287. The reversal of 16521864929257 is 75292946812561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13652699841936 + 2869165087321 = 3694956^2 + 1693861^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16521864929257 is a prime.

It is a super-2 number, since 2×16521864929257² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 16521864929192 and 16521864929201.

It is not a weakly prime, because it can be changed into another prime (16521864929287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8260932464628 + 8260932464629.

It is an arithmetic number, because the mean of its divisors is an integer number (8260932464629).

Almost surely, 2^{16521864929257} is an apocalyptic number.

It is an amenable number.

16521864929257 is a deficient number, since it is larger than the sum of its proper divisors (1).

16521864929257 is an equidigital number, since it uses as much as digits as its factorization.

16521864929257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 130636800, while the sum is 67.

The spelling of 16521864929257 in words is "sixteen trillion, five hundred twenty-one billion, eight hundred sixty-four million, nine hundred twenty-nine thousand, two hundred fifty-seven".