18621021 has 8 divisors (see below), whose sum is σ = 25405600. Its totient is φ = 12125232.

The previous prime is 18621019. The next prime is 18621023. The reversal of 18621021 is 12012681.

It is an interprime number because it is at equal distance from previous prime (18621019) and next prime (18621023).

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

It is not a de Polignac number, because 18621021 - 2¹ = 18621019 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 (18621023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 72046 + ... + 72303.

It is an arithmetic number, because the mean of its divisors is an integer number (3175700).

Almost surely, 2^18621021 is an apocalyptic number.

It is an amenable number.

18621021 is a deficient number, since it is larger than the sum of its proper divisors (6784579).

18621021 is a wasteful number, since it uses less digits than its factorization.

18621021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144395.

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 18621021 is about 4315.2081062215. The cubic root of 18621021 is about 265.0540817591.

The spelling of 18621021 in words is "eighteen million, six hundred twenty-one thousand, twenty-one".