28128623 has 2 divisors, whose sum is σ = 28128624. Its totient is φ = 28128622.

The previous prime is 28128619. The next prime is 28128629. The reversal of 28128623 is 32682182.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28128623 - 2² = 28128619 is a prime.

It is a super-2 number, since 2×28128623² = 1582438863752258, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28128623.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28128629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14064311 + 14064312.

It is an arithmetic number, because the mean of its divisors is an integer number (14064312).

Almost surely, 2^28128623 is an apocalyptic number.

28128623 is a deficient number, since it is larger than the sum of its proper divisors (1).

28128623 is an equidigital number, since it uses as much as digits as its factorization.

28128623 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9216, while the sum is 32.

The square root of 28128623 is about 5303.6424276152. The cubic root of 28128623 is about 304.1231574804.

The spelling of 28128623 in words is "twenty-eight million, one hundred twenty-eight thousand, six hundred twenty-three".