8641621 has 2 divisors, whose sum is σ = 8641622. Its totient is φ = 8641620.

The previous prime is 8641613. The next prime is 8641631. The reversal of 8641621 is 1261468.

8641621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4796100 + 3845521 = 2190^2 + 1961^2 .

It is a cyclic number.

It is not a de Polignac number, because 8641621 - 2³ = 8641613 is a prime.

It is a super-2 number, since 2×8641621² = 149355227015282, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 8641621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8641631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4320810 + 4320811.

It is an arithmetic number, because the mean of its divisors is an integer number (4320811).

Almost surely, 2^8641621 is an apocalyptic number.

It is an amenable number.

8641621 is a deficient number, since it is larger than the sum of its proper divisors (1).

8641621 is an equidigital number, since it uses as much as digits as its factorization.

8641621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 28.

The square root of 8641621 is about 2939.6634161074. The cubic root of 8641621 is about 205.2099455349.

It can be divided in two parts, 864 and 1621, that added together give a triangular number (2485 = T₇₀).

The spelling of 8641621 in words is "eight million, six hundred forty-one thousand, six hundred twenty-one".