28817581 has 8 divisors (see below), whose sum is σ = 31077144. Its totient is φ = 26564160.

The previous prime is 28817573. The next prime is 28817603. The reversal of 28817581 is 18571882.

It can be written as a sum of positive squares in 4 ways, for example, as 6812100 + 22005481 = 2610^2 + 4691^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28817581 - 2³ = 28817573 is a prime.

It is a super-2 number, since 2×28817581² = 1660905949383122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28817501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14415 + ... + 16291.

It is an arithmetic number, because the mean of its divisors is an integer number (3884643).

Almost surely, 2^28817581 is an apocalyptic number.

It is an amenable number.

28817581 is a deficient number, since it is larger than the sum of its proper divisors (2259563).

28817581 is a wasteful number, since it uses less digits than its factorization.

28817581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3071.

The product of its digits is 35840, while the sum is 40.

The square root of 28817581 is about 5368.2009090570. The cubic root of 28817581 is about 306.5861328909.

The spelling of 28817581 in words is "twenty-eight million, eight hundred seventeen thousand, five hundred eighty-one".