28370781 has 24 divisors (see below), whose sum is σ = 43374240. Its totient is φ = 17820000.

The previous prime is 28370777. The next prime is 28370827. The reversal of 28370781 is 18707382.

It is not a de Polignac number, because 28370781 - 2² = 28370777 is a prime.

It is a super-2 number, since 2×28370781² = 1609802429099922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28370701) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42591 + ... + 43251.

It is an arithmetic number, because the mean of its divisors is an integer number (1807260).

Almost surely, 2^28370781 is an apocalyptic number.

It is an amenable number.

28370781 is a deficient number, since it is larger than the sum of its proper divisors (15003459).

28370781 is a wasteful number, since it uses less digits than its factorization.

28370781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 937 (or 934 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 28370781 is about 5326.4229084818. The cubic root of 28370781 is about 304.9933923141.

The spelling of 28370781 in words is "twenty-eight million, three hundred seventy thousand, seven hundred eighty-one".