28365556691 has 2 divisors, whose sum is σ = 28365556692. Its totient is φ = 28365556690.

The previous prime is 28365556657. The next prime is 28365556717. The reversal of 28365556691 is 19665556382.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28365556691 is a prime.

It is not a weakly prime, because it can be changed into another prime (28365556621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14182778345 + 14182778346.

It is an arithmetic number, because the mean of its divisors is an integer number (14182778346).

Almost surely, 2^28365556691 is an apocalyptic number.

28365556691 is a deficient number, since it is larger than the sum of its proper divisors (1).

28365556691 is an equidigital number, since it uses as much as digits as its factorization.

28365556691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664000, while the sum is 56.

The spelling of 28365556691 in words is "twenty-eight billion, three hundred sixty-five million, five hundred fifty-six thousand, six hundred ninety-one".