28668037621 has 2 divisors, whose sum is σ = 28668037622. Its totient is φ = 28668037620.

The previous prime is 28668037603. The next prime is 28668037631. The reversal of 28668037621 is 12673086682.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18275254596 + 10392783025 = 135186^2 + 101945^2 .

It is a cyclic number.

It is not a de Polignac number, because 28668037621 - 2⁹ = 28668037109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28668037631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14334018810 + 14334018811.

It is an arithmetic number, because the mean of its divisors is an integer number (14334018811).

Almost surely, 2^28668037621 is an apocalyptic number.

It is an amenable number.

28668037621 is a deficient number, since it is larger than the sum of its proper divisors (1).

28668037621 is an equidigital number, since it uses as much as digits as its factorization.

28668037621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1161216, while the sum is 49.

The spelling of 28668037621 in words is "twenty-eight billion, six hundred sixty-eight million, thirty-seven thousand, six hundred twenty-one".