28391870 has 64 divisors (see below), whose sum is σ = 60419520. Its totient is φ = 9504768.

The previous prime is 28391861. The next prime is 28391873. The reversal of 28391870 is 7819382.

28391870 = T₇₆₄ + T₇₆₅ + ... + T₈₅₀.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28391873) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 63869 + ... + 64311.

It is an arithmetic number, because the mean of its divisors is an integer number (944055).

Almost surely, 2^28391870 is an apocalyptic number.

28391870 is an abundant number, since it is smaller than the sum of its proper divisors (32027650).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28391870 is a wasteful number, since it uses less digits than its factorization.

28391870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 509.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 28391870 is about 5328.4021995341. The cubic root of 28391870 is about 305.0689443712.

The spelling of 28391870 in words is "twenty-eight million, three hundred ninety-one thousand, eight hundred seventy".