18211111980 has 48 divisors (see below), whose sum is σ = 51202735584. Its totient is φ = 4836142080.

The previous prime is 18211111973. The next prime is 18211111987. The reversal of 18211111980 is 8911111281.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (18211111973) and next prime (18211111987).

It is not an unprimeable number, because it can be changed into a prime (18211111987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 615247 + ... + 644166.

It is an arithmetic number, because the mean of its divisors is an integer number (1066723658).

Almost surely, 2^18211111980 is an apocalyptic number.

18211111980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18211111980 is an abundant number, since it is smaller than the sum of its proper divisors (32991623604).

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

18211111980 is a wasteful number, since it uses less digits than its factorization.

18211111980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1259666 (or 1259664 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 33.

The spelling of 18211111980 in words is "eighteen billion, two hundred eleven million, one hundred eleven thousand, nine hundred eighty".