18720028 has 6 divisors (see below), whose sum is σ = 32760056. Its totient is φ = 9360012.

The previous prime is 18719983. The next prime is 18720083. The reversal of 18720028 is 82002781.

It is a junction number, because it is equal to n+sod(n) for n = 18719978 and 18720005.

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, 2340000 + ... + 2340007.

Almost surely, 2^18720028 is an apocalyptic number.

It is an amenable number.

18720028 is a deficient number, since it is larger than the sum of its proper divisors (14040028).

18720028 is a wasteful number, since it uses less digits than its factorization.

18720028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4680011 (or 4680009 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 28.

The square root of 18720028 is about 4326.6647663067. The cubic root of 18720028 is about 265.5230112355.

The spelling of 18720028 in words is "eighteen million, seven hundred twenty thousand, twenty-eight".