18841621 has 8 divisors (see below), whose sum is σ = 19440344. Its totient is φ = 18247680.

The previous prime is 18841609. The next prime is 18841633. The reversal of 18841621 is 12614881.

It is an interprime number because it is at equal distance from previous prime (18841609) and next prime (18841633).

It can be written as a sum of positive squares in 4 ways, for example, as 2528100 + 16313521 = 1590^2 + 4039^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18841621 - 2¹¹ = 18839573 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 (18841601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7861 + ... + 9973.

It is an arithmetic number, because the mean of its divisors is an integer number (2430043).

Almost surely, 2^18841621 is an apocalyptic number.

It is an amenable number.

18841621 is a deficient number, since it is larger than the sum of its proper divisors (598723).

18841621 is a wasteful number, since it uses less digits than its factorization.

18841621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2391.

The product of its digits is 3072, while the sum is 31.

The square root of 18841621 is about 4340.6936081691. The cubic root of 18841621 is about 266.0966586742.

The spelling of 18841621 in words is "eighteen million, eight hundred forty-one thousand, six hundred twenty-one".