28643780 has 24 divisors (see below), whose sum is σ = 65620800. Its totient is φ = 10415840.

The previous prime is 28643761. The next prime is 28643801. The reversal of 28643780 is 8734682.

It is a super-2 number, since 2×28643780² = 1640932265376800, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 64880 + ... + 65319.

It is an arithmetic number, because the mean of its divisors is an integer number (2734200).

Almost surely, 2^28643780 is an apocalyptic number.

28643780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28643780 is an abundant number, since it is smaller than the sum of its proper divisors (36977020).

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

28643780 is a wasteful number, since it uses less digits than its factorization.

28643780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130219 (or 130217 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 38.

The square root of 28643780 is about 5351.9884155331. The cubic root of 28643780 is about 305.9685416277.

The spelling of 28643780 in words is "twenty-eight million, six hundred forty-three thousand, seven hundred eighty".