16528285721 has 2 divisors, whose sum is σ = 16528285722. Its totient is φ = 16528285720.

The previous prime is 16528285681. The next prime is 16528285727. The reversal of 16528285721 is 12758282561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16444471696 + 83814025 = 128236^2 + 9155^2 .

It is a cyclic number.

It is not a de Polignac number, because 16528285721 - 2¹⁴ = 16528269337 is a prime.

It is not a weakly prime, because it can be changed into another prime (16528285727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8264142860 + 8264142861.

It is an arithmetic number, because the mean of its divisors is an integer number (8264142861).

Almost surely, 2^16528285721 is an apocalyptic number.

It is an amenable number.

16528285721 is a deficient number, since it is larger than the sum of its proper divisors (1).

16528285721 is an equidigital number, since it uses as much as digits as its factorization.

16528285721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 537600, while the sum is 47.

The spelling of 16528285721 in words is "sixteen billion, five hundred twenty-eight million, two hundred eighty-five thousand, seven hundred twenty-one".