1821880980 has 36 divisors (see below), whose sum is σ = 5526372852. Its totient is φ = 485834880.

The previous prime is 1821880979. The next prime is 1821880981. The reversal of 1821880980 is 890881281.

It is an interprime number because it is at equal distance from previous prime (1821880979) and next prime (1821880981).

It can be written as a sum of positive squares in 2 ways, for example, as 959636484 + 862244496 = 30978^2 + 29364^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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 (1821880981) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5060601 + ... + 5060960.

It is an arithmetic number, because the mean of its divisors is an integer number (153510357).

Almost surely, 2^1821880980 is an apocalyptic number.

1821880980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1821880980 is an abundant number, since it is smaller than the sum of its proper divisors (3704491872).

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

1821880980 is a wasteful number, since it uses less digits than its factorization.

1821880980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10121576 (or 10121571 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 45.

The square root of 1821880980 is about 42683.4977479588. The cubic root of 1821880980 is about 1221.3496172564.

The spelling of 1821880980 in words is "one billion, eight hundred twenty-one million, eight hundred eighty thousand, nine hundred eighty".