28931641 has 2 divisors, whose sum is σ = 28931642. Its totient is φ = 28931640.

The previous prime is 28931621. The next prime is 28931657. The reversal of 28931641 is 14613982.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21114025 + 7817616 = 4595^2 + 2796^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28931641 is a prime.

It is equal to p_1795723 and since 28931641 and 1795723 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 28931597 and 28931606.

It is not a weakly prime, because it can be changed into another prime (28931611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14465820 + 14465821.

It is an arithmetic number, because the mean of its divisors is an integer number (14465821).

Almost surely, 2^28931641 is an apocalyptic number.

It is an amenable number.

28931641 is a deficient number, since it is larger than the sum of its proper divisors (1).

28931641 is an equidigital number, since it uses as much as digits as its factorization.

28931641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 34.

The square root of 28931641 is about 5378.8140886259. The cubic root of 28931641 is about 306.9900897606.

The spelling of 28931641 in words is "twenty-eight million, nine hundred thirty-one thousand, six hundred forty-one".