28028731 has 2 divisors, whose sum is σ = 28028732. Its totient is φ = 28028730.

The previous prime is 28028729. The next prime is 28028747. The reversal of 28028731 is 13782082.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28028731 - 2¹ = 28028729 is a prime.

It is a super-2 number, since 2×28028731² = 1571219522940722, which contains 22 as substring.

Together with 28028729, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 28028693 and 28028702.

It is not a weakly prime, because it can be changed into another prime (28028701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14014365 + 14014366.

It is an arithmetic number, because the mean of its divisors is an integer number (14014366).

Almost surely, 2^28028731 is an apocalyptic number.

28028731 is a deficient number, since it is larger than the sum of its proper divisors (1).

28028731 is an equidigital number, since it uses as much as digits as its factorization.

28028731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 28028731 is about 5294.2167503796. The cubic root of 28028731 is about 303.7627238710.

The spelling of 28028731 in words is "twenty-eight million, twenty-eight thousand, seven hundred thirty-one".