28578215 has 4 divisors (see below), whose sum is σ = 34293864. Its totient is φ = 22862568.

The previous prime is 28578211. The next prime is 28578217. The reversal of 28578215 is 51287582.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 51287582 = 2 ⋅25643791.

It is a cyclic number.

It is not a de Polignac number, because 28578215 - 2² = 28578211 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28578211) 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, 2857817 + ... + 2857826.

It is an arithmetic number, because the mean of its divisors is an integer number (8573466).

Almost surely, 2^28578215 is an apocalyptic number.

28578215 is a deficient number, since it is larger than the sum of its proper divisors (5715649).

28578215 is an equidigital number, since it uses as much as digits as its factorization.

28578215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5715648.

The product of its digits is 44800, while the sum is 38.

The square root of 28578215 is about 5345.8596128219. The cubic root of 28578215 is about 305.7349114621.

The spelling of 28578215 in words is "twenty-eight million, five hundred seventy-eight thousand, two hundred fifteen".