1816129980 has 72 divisors (see below), whose sum is σ = 6295921632. Its totient is φ = 415115136.

The previous prime is 1816129963. The next prime is 1816129981. The reversal of 1816129980 is 899216181.

It is a Smith number, since the sum of its digits (45) 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 (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1816129981) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 719427 + ... + 721946.

It is an arithmetic number, because the mean of its divisors is an integer number (87443356).

Almost surely, 2^1816129980 is an apocalyptic number.

1816129980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1816129980 is an abundant number, since it is smaller than the sum of its proper divisors (4479791652).

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

1816129980 is a wasteful number, since it uses less digits than its factorization.

1816129980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1441395 (or 1441390 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 45.

The square root of 1816129980 is about 42616.0765439523. The cubic root of 1816129980 is about 1220.0631473182.

The spelling of 1816129980 in words is "one billion, eight hundred sixteen million, one hundred twenty-nine thousand, nine hundred eighty".