28406690 has 16 divisors (see below), whose sum is σ = 55065528. Its totient is φ = 10488576.

The previous prime is 28406647. The next prime is 28406699. The reversal of 28406690 is 9660482.

It can be written as a sum of positive squares in 4 ways, for example, as 11621281 + 16785409 = 3409^2 + 4097^2 .

It is a super-2 number, since 2×28406690² = 1613880073512200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28406690.

It is not an unprimeable number, because it can be changed into a prime (28406699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 109127 + ... + 109386.

Almost surely, 2^28406690 is an apocalyptic number.

28406690 is a deficient number, since it is larger than the sum of its proper divisors (26658838).

28406690 is a wasteful number, since it uses less digits than its factorization.

28406690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218533.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 28406690 is about 5329.7926788947. The cubic root of 28406690 is about 305.1220151427.

The spelling of 28406690 in words is "twenty-eight million, four hundred six thousand, six hundred ninety".