28665690 has 32 divisors (see below), whose sum is σ = 68938560. Its totient is φ = 7628544.

The previous prime is 28665677. The next prime is 28665691. The reversal of 28665690 is 9656682.

It is a super-4 number, since 4×28665690⁴ (a number of 31 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28665691) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27906 + ... + 28914.

It is an arithmetic number, because the mean of its divisors is an integer number (2154330).

Almost surely, 2^28665690 is an apocalyptic number.

28665690 is an abundant number, since it is smaller than the sum of its proper divisors (40272870).

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

28665690 is a wasteful number, since it uses less digits than its factorization.

28665690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1966.

The product of its (nonzero) digits is 155520, while the sum is 42.

The square root of 28665690 is about 5354.0349270433. The cubic root of 28665690 is about 306.0465348512.

The spelling of 28665690 in words is "twenty-eight million, six hundred sixty-five thousand, six hundred ninety".