28783381 has 4 divisors (see below), whose sum is σ = 31400064. Its totient is φ = 26166700.

The previous prime is 28783369. The next prime is 28783387. The reversal of 28783381 is 18338782.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28783381 - 2²¹ = 26686229 is a prime.

It is a super-2 number, since 2×28783381² = 1656966043582322, 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 (28783387) 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, 1308325 + ... + 1308346.

It is an arithmetic number, because the mean of its divisors is an integer number (7850016).

Almost surely, 2^28783381 is an apocalyptic number.

It is an amenable number.

28783381 is a deficient number, since it is larger than the sum of its proper divisors (2616683).

28783381 is a wasteful number, since it uses less digits than its factorization.

28783381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2616682.

The product of its digits is 64512, while the sum is 40.

The square root of 28783381 is about 5365.0145386569. The cubic root of 28783381 is about 306.4648019071.

The spelling of 28783381 in words is "twenty-eight million, seven hundred eighty-three thousand, three hundred eighty-one".