28903991 has 2 divisors, whose sum is σ = 28903992. Its totient is φ = 28903990.

The previous prime is 28903957. The next prime is 28904009. The reversal of 28903991 is 19930982.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28903991 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28903951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14451995 + 14451996.

It is an arithmetic number, because the mean of its divisors is an integer number (14451996).

Almost surely, 2^28903991 is an apocalyptic number.

28903991 is a deficient number, since it is larger than the sum of its proper divisors (1).

28903991 is an equidigital number, since it uses as much as digits as its factorization.

28903991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 41.

The square root of 28903991 is about 5376.2432050643. The cubic root of 28903991 is about 306.8922616710.

The spelling of 28903991 in words is "twenty-eight million, nine hundred three thousand, nine hundred ninety-one".