28663381 has 8 divisors (see below), whose sum is σ = 30222720. Its totient is φ = 27109152.

The previous prime is 28663367. The next prime is 28663409. The reversal of 28663381 is 18336682.

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 28663381 - 2⁷ = 28663253 is a prime.

It is a super-2 number, since 2×28663381² = 1643178820702322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28663381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28663361) 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, 17316 + ... + 18898.

It is an arithmetic number, because the mean of its divisors is an integer number (3777840).

Almost surely, 2^28663381 is an apocalyptic number.

It is an amenable number.

28663381 is a deficient number, since it is larger than the sum of its proper divisors (1559339).

28663381 is a wasteful number, since it uses less digits than its factorization.

28663381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2555.

The product of its digits is 41472, while the sum is 37.

The square root of 28663381 is about 5353.8192909361. The cubic root of 28663381 is about 306.0383173570.

The spelling of 28663381 in words is "twenty-eight million, six hundred sixty-three thousand, three hundred eighty-one".