28639215 has 48 divisors (see below), whose sum is σ = 55351296. Its totient is φ = 13579200.

The previous prime is 28639207. The next prime is 28639223. The reversal of 28639215 is 51293682.

28639215 is a `hidden beast` number, since 2 + 8 + 639 + 2 + 15 = 666.

It is an interprime number because it is at equal distance from previous prime (28639207) and next prime (28639223).

It is not a de Polignac number, because 28639215 - 2³ = 28639207 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28639215.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22650 + ... + 23880.

It is an arithmetic number, because the mean of its divisors is an integer number (1153152).

Almost surely, 2^28639215 is an apocalyptic number.

28639215 is a deficient number, since it is larger than the sum of its proper divisors (26712081).

28639215 is a wasteful number, since it uses less digits than its factorization.

28639215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1300 (or 1297 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 28639215 is about 5351.5619215328. The cubic root of 28639215 is about 305.9522865501.

The spelling of 28639215 in words is "twenty-eight million, six hundred thirty-nine thousand, two hundred fifteen".