18821606 has 4 divisors (see below), whose sum is σ = 28232412. Its totient is φ = 9410802.

The previous prime is 18821599. The next prime is 18821617. The reversal of 18821606 is 60612881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60612881 = 7 ⋅8658983.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4705400 + ... + 4705403.

It is an arithmetic number, because the mean of its divisors is an integer number (7058103).

Almost surely, 2^18821606 is an apocalyptic number.

18821606 is a deficient number, since it is larger than the sum of its proper divisors (9410806).

18821606 is an equidigital number, since it uses as much as digits as its factorization.

18821606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9410805.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 18821606 is about 4338.3874884570. The cubic root of 18821606 is about 266.0024026014.

The spelling of 18821606 in words is "eighteen million, eight hundred twenty-one thousand, six hundred six".