28501621 has 2 divisors, whose sum is σ = 28501622. Its totient is φ = 28501620.

The previous prime is 28501597. The next prime is 28501657. The reversal of 28501621 is 12610582.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18610596 + 9891025 = 4314^2 + 3145^2 .

It is a cyclic number.

It is not a de Polignac number, because 28501621 - 2⁵ = 28501589 is a prime.

It is equal to p_1770703 and since 28501621 and 1770703 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28501021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14250810 + 14250811.

It is an arithmetic number, because the mean of its divisors is an integer number (14250811).

Almost surely, 2^28501621 is an apocalyptic number.

It is an amenable number.

28501621 is a deficient number, since it is larger than the sum of its proper divisors (1).

28501621 is an equidigital number, since it uses as much as digits as its factorization.

28501621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 28501621 is about 5338.6909444170. The cubic root of 28501621 is about 305.4615282597.

The spelling of 28501621 in words is "twenty-eight million, five hundred one thousand, six hundred twenty-one".