28569997 has 4 divisors (see below), whose sum is σ = 28591420. Its totient is φ = 28548576.

The previous prime is 28569973. The next prime is 28570001. The reversal of 28569997 is 79996582.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8328996 + 20241001 = 2886^2 + 4499^2 .

It is a 3-Lehmer number, since φ(28569997) divides (28569997-1)³.

It is a cyclic number.

It is not a de Polignac number, because 28569997 - 2⁷ = 28569869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28569917) 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, 8568 + ... + 11425.

It is an arithmetic number, because the mean of its divisors is an integer number (7147855).

Almost surely, 2^28569997 is an apocalyptic number.

It is an amenable number.

28569997 is a deficient number, since it is larger than the sum of its proper divisors (21423).

28569997 is a wasteful number, since it uses less digits than its factorization.

28569997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21422.

The product of its digits is 2449440, while the sum is 55.

The square root of 28569997 is about 5345.0909253258. The cubic root of 28569997 is about 305.7056027692.

It can be divided in two parts, 28 and 569997, that added together give a square (570025 = 755²).

The spelling of 28569997 in words is "twenty-eight million, five hundred sixty-nine thousand, nine hundred ninety-seven".