28691830 has 16 divisors (see below), whose sum is σ = 52104384. Its totient is φ = 11374720.

The previous prime is 28691753. The next prime is 28691837. The reversal of 28691830 is 3819682.

It is a super-2 number, since 2×28691830² = 1646442217497800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28691830.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28691837) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11566 + ... + 13825.

It is an arithmetic number, because the mean of its divisors is an integer number (3256524).

Almost surely, 2^28691830 is an apocalyptic number.

28691830 is a deficient number, since it is larger than the sum of its proper divisors (23412554).

28691830 is a wasteful number, since it uses less digits than its factorization.

28691830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25511.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 28691830 is about 5356.4755203398. The cubic root of 28691830 is about 306.1395336699.

The spelling of 28691830 in words is "twenty-eight million, six hundred ninety-one thousand, eight hundred thirty".