28837981 has 2 divisors, whose sum is σ = 28837982. Its totient is φ = 28837980.

The previous prime is 28837969. The next prime is 28837987. The reversal of 28837981 is 18973882.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28783225 + 54756 = 5365^2 + 234^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28837981 is a prime.

It is a super-2 number, since 2×28837981² = 1663258296312722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28837987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14418990 + 14418991.

It is an arithmetic number, because the mean of its divisors is an integer number (14418991).

Almost surely, 2^28837981 is an apocalyptic number.

It is an amenable number.

28837981 is a deficient number, since it is larger than the sum of its proper divisors (1).

28837981 is an equidigital number, since it uses as much as digits as its factorization.

28837981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 193536, while the sum is 46.

The square root of 28837981 is about 5370.1006508258. The cubic root of 28837981 is about 306.6584600566.

The spelling of 28837981 in words is "twenty-eight million, eight hundred thirty-seven thousand, nine hundred eighty-one".