28724369 has 4 divisors (see below), whose sum is σ = 28917300. Its totient is φ = 28531440.

The previous prime is 28724363. The next prime is 28724419. The reversal of 28724369 is 96342782.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96342782 = 2 ⋅48171391.

It can be written as a sum of positive squares in 2 ways, for example, as 1809025 + 26915344 = 1345^2 + 5188^2 .

It is a cyclic number.

It is not a de Polignac number, because 28724369 - 2¹² = 28720273 is a prime.

It is a super-2 number, since 2×28724369² = 1650178748896322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28724363) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96242 + ... + 96539.

It is an arithmetic number, because the mean of its divisors is an integer number (7229325).

Almost surely, 2^28724369 is an apocalyptic number.

It is an amenable number.

28724369 is a deficient number, since it is larger than the sum of its proper divisors (192931).

28724369 is a wasteful number, since it uses less digits than its factorization.

28724369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192930.

The product of its digits is 145152, while the sum is 41.

The square root of 28724369 is about 5359.5120113682. The cubic root of 28724369 is about 306.2552194585.

Adding to 28724369 its sum of digits (41), we get a triangular number (28724410 = T₇₅₇₉).

The spelling of 28724369 in words is "twenty-eight million, seven hundred twenty-four thousand, three hundred sixty-nine".