28870991 has 2 divisors, whose sum is σ = 28870992. Its totient is φ = 28870990.

The previous prime is 28870973. The next prime is 28870997. The reversal of 28870991 is 19907882.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28870991 - 2⁶ = 28870927 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28870997) 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, 14435495 + 14435496.

It is an arithmetic number, because the mean of its divisors is an integer number (14435496).

Almost surely, 2^28870991 is an apocalyptic number.

28870991 is a deficient number, since it is larger than the sum of its proper divisors (1).

28870991 is an equidigital number, since it uses as much as digits as its factorization.

28870991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 28870991 is about 5373.1732709824. The cubic root of 28870991 is about 306.7754231200.

The spelling of 28870991 in words is "twenty-eight million, eight hundred seventy thousand, nine hundred ninety-one".