28691011 has 4 divisors (see below), whose sum is σ = 28733224. Its totient is φ = 28648800.

The previous prime is 28690997. The next prime is 28691017. The reversal of 28691011 is 11019682.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28691011 - 2⁵ = 28690979 is a prime.

It is a super-2 number, since 2×28691011² = 1646348224404242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28691017) 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 3 ways as a sum of consecutive naturals, for example, 20070 + ... + 21451.

It is an arithmetic number, because the mean of its divisors is an integer number (7183306).

Almost surely, 2^28691011 is an apocalyptic number.

28691011 is a deficient number, since it is larger than the sum of its proper divisors (42213).

28691011 is an equidigital number, since it uses as much as digits as its factorization.

28691011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42212.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 28691011 is about 5356.3990702710. The cubic root of 28691011 is about 306.1366207540.

The spelling of 28691011 in words is "twenty-eight million, six hundred ninety-one thousand, eleven".