28506121979 has 2 divisors, whose sum is σ = 28506121980. Its totient is φ = 28506121978.

The previous prime is 28506121939. The next prime is 28506121981. The reversal of 28506121979 is 97912160582.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28506121979 is a prime.

Together with 28506121981, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28506121939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14253060989 + 14253060990.

It is an arithmetic number, because the mean of its divisors is an integer number (14253060990).

Almost surely, 2^28506121979 is an apocalyptic number.

28506121979 is a deficient number, since it is larger than the sum of its proper divisors (1).

28506121979 is an equidigital number, since it uses as much as digits as its factorization.

28506121979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 544320, while the sum is 50.

The spelling of 28506121979 in words is "twenty-eight billion, five hundred six million, one hundred twenty-one thousand, nine hundred seventy-nine".