28973621 has 2 divisors, whose sum is σ = 28973622. Its totient is φ = 28973620.

The previous prime is 28973611. The next prime is 28973657. The reversal of 28973621 is 12637982.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23280625 + 5692996 = 4825^2 + 2386^2 .

It is a cyclic number.

It is not a de Polignac number, because 28973621 - 2¹⁰ = 28972597 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28973611) 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 as a sum of consecutive naturals, namely, 14486810 + 14486811.

It is an arithmetic number, because the mean of its divisors is an integer number (14486811).

Almost surely, 2^28973621 is an apocalyptic number.

It is an amenable number.

28973621 is a deficient number, since it is larger than the sum of its proper divisors (1).

28973621 is an equidigital number, since it uses as much as digits as its factorization.

28973621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 38.

The square root of 28973621 is about 5382.7150212509. The cubic root of 28973621 is about 307.1384995441.

The spelling of 28973621 in words is "twenty-eight million, nine hundred seventy-three thousand, six hundred twenty-one".