16521478439 has 2 divisors, whose sum is σ = 16521478440. Its totient is φ = 16521478438.

The previous prime is 16521478307. The next prime is 16521478451. The reversal of 16521478439 is 93487412561.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 16521478439 - 2²⁸ = 16253042983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16521478459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8260739219 + 8260739220.

It is an arithmetic number, because the mean of its divisors is an integer number (8260739220).

Almost surely, 2^16521478439 is an apocalyptic number.

16521478439 is a deficient number, since it is larger than the sum of its proper divisors (1).

16521478439 is an equidigital number, since it uses as much as digits as its factorization.

16521478439 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1451520, while the sum is 50.

The spelling of 16521478439 in words is "sixteen billion, five hundred twenty-one million, four hundred seventy-eight thousand, four hundred thirty-nine".