18820556 has 6 divisors (see below), whose sum is σ = 32935980. Its totient is φ = 9410276.

The previous prime is 18820553. The next prime is 18820573. The reversal of 18820556 is 65502881.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (18820553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2352566 + ... + 2352573.

It is an arithmetic number, because the mean of its divisors is an integer number (5489330).

Almost surely, 2^18820556 is an apocalyptic number.

It is an amenable number.

18820556 is a deficient number, since it is larger than the sum of its proper divisors (14115424).

18820556 is a wasteful number, since it uses less digits than its factorization.

18820556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4705143 (or 4705141 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 35.

The square root of 18820556 is about 4338.2664740654. The cubic root of 18820556 is about 265.9974560218.

The spelling of 18820556 in words is "eighteen million, eight hundred twenty thousand, five hundred fifty-six".