18606421 has 4 divisors (see below), whose sum is σ = 18647244. Its totient is φ = 18565600.

The previous prime is 18606391. The next prime is 18606433. The reversal of 18606421 is 12460681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13032100 + 5574321 = 3610^2 + 2361^2 .

It is a cyclic number.

It is not a de Polignac number, because 18606421 - 2¹¹ = 18604373 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18606421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18606121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19720 + ... + 20641.

It is an arithmetic number, because the mean of its divisors is an integer number (4661811).

Almost surely, 2^18606421 is an apocalyptic number.

It is an amenable number.

18606421 is a deficient number, since it is larger than the sum of its proper divisors (40823).

18606421 is an equidigital number, since it uses as much as digits as its factorization.

18606421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40822.

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

The square root of 18606421 is about 4313.5160831971. The cubic root of 18606421 is about 264.9847908680.

It can be divided in two parts, 1860 and 6421, that added together give a square (8281 = 91²).

The spelling of 18606421 in words is "eighteen million, six hundred six thousand, four hundred twenty-one".