28069661 has 4 divisors (see below), whose sum is σ = 28224924. Its totient is φ = 27914400.

The previous prime is 28069649. The next prime is 28069673. The reversal of 28069661 is 16696082.

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

It is an interprime number because it is at equal distance from previous prime (28069649) and next prime (28069673).

It can be written as a sum of positive squares in 2 ways, for example, as 1092025 + 26977636 = 1045^2 + 5194^2 .

It is a cyclic number.

It is not a de Polignac number, because 28069661 - 2⁶ = 28069597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28069681) 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, 77360 + ... + 77721.

It is an arithmetic number, because the mean of its divisors is an integer number (7056231).

Almost surely, 2^28069661 is an apocalyptic number.

It is an amenable number.

28069661 is a deficient number, since it is larger than the sum of its proper divisors (155263).

28069661 is a wasteful number, since it uses less digits than its factorization.

28069661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155262.

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 28069661 is about 5298.0808789599. The cubic root of 28069661 is about 303.9105122395.

The spelling of 28069661 in words is "twenty-eight million, sixty-nine thousand, six hundred sixty-one".