1817861980 has 96 divisors (see below), whose sum is σ = 4334964480. Its totient is φ = 634529280.

The previous prime is 1817861959. The next prime is 1817861989. The reversal of 1817861980 is 891687181.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1817861989) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 556512 + ... + 559768.

It is an arithmetic number, because the mean of its divisors is an integer number (45155880).

Almost surely, 2^1817861980 is an apocalyptic number.

1817861980 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 1817861980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2167482240).

1817861980 is an abundant number, since it is smaller than the sum of its proper divisors (2517102500).

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

1817861980 is a wasteful number, since it uses less digits than its factorization.

1817861980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3379 (or 3377 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 49.

The square root of 1817861980 is about 42636.3926710504. The cubic root of 1817861980 is about 1220.4508724988.

The spelling of 1817861980 in words is "one billion, eight hundred seventeen million, eight hundred sixty-one thousand, nine hundred eighty".