28724787 has 56 divisors (see below), whose sum is σ = 53128544. Its totient is φ = 15116544.

The previous prime is 28724753. The next prime is 28724797. The reversal of 28724787 is 78742782.

It is not a de Polignac number, because 28724787 - 2¹¹ = 28722739 is a prime.

It is a super-2 number, since 2×28724787² = 1650226776390738, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28724737) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 66123 + ... + 66555.

It is an arithmetic number, because the mean of its divisors is an integer number (948724).

Almost surely, 2^28724787 is an apocalyptic number.

28724787 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

28724787 is a deficient number, since it is larger than the sum of its proper divisors (24403757).

28724787 is an equidigital number, since it uses as much as digits as its factorization.

28724787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471 (or 456 counting only the distinct ones).

The product of its digits is 351232, while the sum is 45.

The square root of 28724787 is about 5359.5510073140. The cubic root of 28724787 is about 306.2567050038.

The spelling of 28724787 in words is "twenty-eight million, seven hundred twenty-four thousand, seven hundred eighty-seven".