28191929 has 2 divisors, whose sum is σ = 28191930. Its totient is φ = 28191928.

The previous prime is 28191923. The next prime is 28191931. The reversal of 28191929 is 92919182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23232400 + 4959529 = 4820^2 + 2227^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28191929 is a prime.

Together with 28191931, 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 (28191923) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14095964 + 14095965.

It is an arithmetic number, because the mean of its divisors is an integer number (14095965).

Almost surely, 2^28191929 is an apocalyptic number.

It is an amenable number.

28191929 is a deficient number, since it is larger than the sum of its proper divisors (1).

28191929 is an equidigital number, since it uses as much as digits as its factorization.

28191929 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 41.

The square root of 28191929 is about 5309.6072359450. The cubic root of 28191929 is about 304.3511387226.

The spelling of 28191929 in words is "twenty-eight million, one hundred ninety-one thousand, nine hundred twenty-nine".