28378897 has 4 divisors (see below), whose sum is σ = 28392676. Its totient is φ = 28365120.

The previous prime is 28378853. The next prime is 28378901. The reversal of 28378897 is 79887382.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79887382 = 2 ⋅39943691.

It can be written as a sum of positive squares in 2 ways, for example, as 9054081 + 19324816 = 3009^2 + 4396^2 .

It is a cyclic number.

It is not a de Polignac number, because 28378897 - 2⁷ = 28378769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28378817) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3108 + ... + 8149.

It is an arithmetic number, because the mean of its divisors is an integer number (7098169).

Almost surely, 2^28378897 is an apocalyptic number.

28378897 is the 2848-th centered heptagonal number.

It is an amenable number.

28378897 is a deficient number, since it is larger than the sum of its proper divisors (13779).

28378897 is a wasteful number, since it uses less digits than its factorization.

28378897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13778.

The product of its digits is 1354752, while the sum is 52.

The square root of 28378897 is about 5327.1847161517. The cubic root of 28378897 is about 305.0224725894.

The spelling of 28378897 in words is "twenty-eight million, three hundred seventy-eight thousand, eight hundred ninety-seven".