18219940 has 24 divisors (see below), whose sum is σ = 39497472. Its totient is φ = 7052640.

The previous prime is 18219923. The next prime is 18219941. The reversal of 18219940 is 4991281.

It is a junction number, because it is equal to n+sod(n) for n = 18219896 and 18219905.

It is not an unprimeable number, because it can be changed into a prime (18219941) 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, 14074 + ... + 15313.

It is an arithmetic number, because the mean of its divisors is an integer number (1645728).

Almost surely, 2^18219940 is an apocalyptic number.

18219940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18219940 is an abundant number, since it is smaller than the sum of its proper divisors (21277532).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18219940 is a wasteful number, since it uses less digits than its factorization.

18219940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29427 (or 29425 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 18219940 is about 4268.4821658290. The cubic root of 18219940 is about 263.1372394034.

The spelling of 18219940 in words is "eighteen million, two hundred nineteen thousand, nine hundred forty".