28223691 has 16 divisors (see below), whose sum is σ = 39398400. Its totient is φ = 17937920.

The previous prime is 28223687. The next prime is 28223717. The reversal of 28223691 is 19632282.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 28223691 - 2² = 28223687 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28223651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30526 + ... + 31436.

It is an arithmetic number, because the mean of its divisors is an integer number (2462400).

Almost surely, 2^28223691 is an apocalyptic number.

28223691 is a deficient number, since it is larger than the sum of its proper divisors (11174709).

28223691 is a wasteful number, since it uses less digits than its factorization.

28223691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1386.

The product of its digits is 10368, while the sum is 33.

The square root of 28223691 is about 5312.5973873427. The cubic root of 28223691 is about 304.4653933239.

The spelling of 28223691 in words is "twenty-eight million, two hundred twenty-three thousand, six hundred ninety-one".