18129780 has 72 divisors (see below), whose sum is σ = 56189952. Its totient is φ = 4729536.

The previous prime is 18129757. The next prime is 18129791. The reversal of 18129780 is 8792181.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7389 + ... + 9531.

It is an arithmetic number, because the mean of its divisors is an integer number (780416).

Almost surely, 2^18129780 is an apocalyptic number.

18129780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18129780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28094976).

18129780 is an abundant number, since it is smaller than the sum of its proper divisors (38060172).

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

18129780 is a wasteful number, since it uses less digits than its factorization.

18129780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2205 (or 2200 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 18129780 is about 4257.9079370038. The cubic root of 18129780 is about 262.7024832272.

The spelling of 18129780 in words is "eighteen million, one hundred twenty-nine thousand, seven hundred eighty".