1821318156 has 96 divisors (see below), whose sum is σ = 5420782080. Its totient is φ = 518035392.

The previous prime is 1821318139. The next prime is 1821318173. The reversal of 1821318156 is 6518131281.

It is an interprime number because it is at equal distance from previous prime (1821318139) and next prime (1821318173).

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

It is a self number, because there is not a number n which added to its sum of digits gives 1821318156.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 166306 + ... + 176918.

It is an arithmetic number, because the mean of its divisors is an integer number (56466480).

Almost surely, 2^1821318156 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1821318156, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2710391040).

1821318156 is an abundant number, since it is smaller than the sum of its proper divisors (3599463924).

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

1821318156 is a wasteful number, since it uses less digits than its factorization.

1821318156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10860 (or 10852 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 1821318156 is about 42676.9042457393. The cubic root of 1821318156 is about 1221.2238359564.

The spelling of 1821318156 in words is "one billion, eight hundred twenty-one million, three hundred eighteen thousand, one hundred fifty-six".