28939724 has 18 divisors (see below), whose sum is σ = 55316772. Its totient is φ = 13138200.

The previous prime is 28939721. The next prime is 28939739. The reversal of 28939724 is 42793982.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is not an unprimeable number, because it can be changed into a prime (28939721) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35279 + ... + 36089.

It is an arithmetic number, because the mean of its divisors is an integer number (3073154).

Almost surely, 2^28939724 is an apocalyptic number.

It is an amenable number.

28939724 is a deficient number, since it is larger than the sum of its proper divisors (26377048).

28939724 is an equidigital number, since it uses as much as digits as its factorization.

28939724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1637 (or 824 counting only the distinct ones).

The product of its digits is 217728, while the sum is 44.

The square root of 28939724 is about 5379.5654099565. The cubic root of 28939724 is about 307.0186763387.

Multiplying 28939724 by its sum of digits (44), we get a square (1273347856 = 35684²).

28939724 divided by its sum of digits (44) gives a square (657721 = 811²).

The spelling of 28939724 in words is "twenty-eight million, nine hundred thirty-nine thousand, seven hundred twenty-four".