28021943 has 2 divisors, whose sum is σ = 28021944. Its totient is φ = 28021942.

The previous prime is 28021919. The next prime is 28021949. The reversal of 28021943 is 34912082.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28021943 - 2¹⁸ = 27759799 is a prime.

It is a Sophie Germain prime.

It is equal to p_1742735 and since 28021943 and 1742735 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28021949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14010971 + 14010972.

It is an arithmetic number, because the mean of its divisors is an integer number (14010972).

Almost surely, 2^28021943 is an apocalyptic number.

28021943 is a deficient number, since it is larger than the sum of its proper divisors (1).

28021943 is an equidigital number, since it uses as much as digits as its factorization.

28021943 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 28021943 is about 5293.5756346727. The cubic root of 28021943 is about 303.7382001321.

The spelling of 28021943 in words is "twenty-eight million, twenty-one thousand, nine hundred forty-three".