28924781 has 2 divisors, whose sum is σ = 28924782. Its totient is φ = 28924780.

The previous prime is 28924757. The next prime is 28924793. The reversal of 28924781 is 18742982.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16883881 + 12040900 = 4109^2 + 3470^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28924781 is a prime.

It is a super-2 number, since 2×28924781² = 1673285911795922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28924711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14462390 + 14462391.

It is an arithmetic number, because the mean of its divisors is an integer number (14462391).

Almost surely, 2^28924781 is an apocalyptic number.

It is an amenable number.

28924781 is a deficient number, since it is larger than the sum of its proper divisors (1).

28924781 is an equidigital number, since it uses as much as digits as its factorization.

28924781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64512, while the sum is 41.

The square root of 28924781 is about 5378.1763637873. The cubic root of 28924781 is about 306.9658243035.

The spelling of 28924781 in words is "twenty-eight million, nine hundred twenty-four thousand, seven hundred eighty-one".