28919721569 has 2 divisors, whose sum is σ = 28919721570. Its totient is φ = 28919721568.

The previous prime is 28919721553. The next prime is 28919721613. The reversal of 28919721569 is 96512791982.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28818457600 + 101263969 = 169760^2 + 10063^2 .

It is a cyclic number.

It is not a de Polignac number, because 28919721569 - 2⁴ = 28919721553 is a prime.

It is a super-2 number, since 2×28919721569² (a number of 22 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (28919721769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14459860784 + 14459860785.

It is an arithmetic number, because the mean of its divisors is an integer number (14459860785).

Almost surely, 2^28919721569 is an apocalyptic number.

It is an amenable number.

28919721569 is a deficient number, since it is larger than the sum of its proper divisors (1).

28919721569 is an equidigital number, since it uses as much as digits as its factorization.

28919721569 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4898880, while the sum is 59.

The spelling of 28919721569 in words is "twenty-eight billion, nine hundred nineteen million, seven hundred twenty-one thousand, five hundred sixty-nine".