18445557 has 8 divisors (see below), whose sum is σ = 26485984. Its totient is φ = 11351088.

The previous prime is 18445547. The next prime is 18445571. The reversal of 18445557 is 75554481.

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

It is not a de Polignac number, because 18445557 - 2⁴ = 18445541 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 472963 = 18445557 / (1 + 8 + 4 + 4 + 5 + 5 + 5 + 7).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18445547) 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, 236443 + ... + 236520.

It is an arithmetic number, because the mean of its divisors is an integer number (3310748).

Almost surely, 2^18445557 is an apocalyptic number.

It is an amenable number.

18445557 is a deficient number, since it is larger than the sum of its proper divisors (8040427).

18445557 is a wasteful number, since it uses less digits than its factorization.

18445557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 472979.

The product of its digits is 112000, while the sum is 39.

The square root of 18445557 is about 4294.8291002088. The cubic root of 18445557 is about 264.2189271009.

The spelling of 18445557 in words is "eighteen million, four hundred forty-five thousand, five hundred fifty-seven".