28293311997 has 6 divisors (see below), whose sum is σ = 40868117342. Its totient is φ = 18862207992.

The previous prime is 28293311993. The next prime is 28293312017. The reversal of 28293311997 is 79911339282.

It can be written as a sum of positive squares in only one way, i.e., 22421768121 + 5871543876 = 149739^2 + 76626^2 .

It is not a de Polignac number, because 28293311997 - 2² = 28293311993 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28293311993) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1571850658 + ... + 1571850675.

Almost surely, 2^28293311997 is an apocalyptic number.

It is an amenable number.

28293311997 is a deficient number, since it is larger than the sum of its proper divisors (12574805345).

28293311997 is a wasteful number, since it uses less digits than its factorization.

28293311997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3143701339 (or 3143701336 counting only the distinct ones).

The product of its digits is 1469664, while the sum is 54.

The spelling of 28293311997 in words is "twenty-eight billion, two hundred ninety-three million, three hundred eleven thousand, nine hundred ninety-seven".