28233661 has 4 divisors (see below), whose sum is σ = 28245024. Its totient is φ = 28222300.

The previous prime is 28233637. The next prime is 28233691. The reversal of 28233661 is 16633282.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 16633282 = 2 ⋅8316641.

It is a cyclic number.

It is not a de Polignac number, because 28233661 - 2⁵ = 28233629 is a prime.

It is a super-2 number, since 2×28233661² = 1594279226925842, 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 (28233631) 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, 175 + ... + 7516.

It is an arithmetic number, because the mean of its divisors is an integer number (7061256).

Almost surely, 2^28233661 is an apocalyptic number.

It is an amenable number.

28233661 is a deficient number, since it is larger than the sum of its proper divisors (11363).

28233661 is an equidigital number, since it uses as much as digits as its factorization.

28233661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11362.

The product of its digits is 10368, while the sum is 31.

The square root of 28233661 is about 5313.5356402305. The cubic root of 28233661 is about 304.5012398356.

The spelling of 28233661 in words is "twenty-eight million, two hundred thirty-three thousand, six hundred sixty-one".