28809690 has 128 divisors (see below), whose sum is σ = 86994432. Its totient is φ = 5944320.

The previous prime is 28809667. The next prime is 28809691. The reversal of 28809690 is 9690882.

It is a super-2 number, since 2×28809690² = 1659996475792200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (28809691) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 166444 + ... + 166616.

It is an arithmetic number, because the mean of its divisors is an integer number (679644).

Almost surely, 2^28809690 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28809690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43497216).

28809690 is an abundant number, since it is smaller than the sum of its proper divisors (58184742).

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

28809690 is a wasteful number, since it uses less digits than its factorization.

28809690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 264.

The product of its (nonzero) digits is 62208, while the sum is 42.

The square root of 28809690 is about 5367.4658825185. The cubic root of 28809690 is about 306.5581465952.

The spelling of 28809690 in words is "twenty-eight million, eight hundred nine thousand, six hundred ninety".