1821609505772 has 12 divisors (see below), whose sum is σ = 3643219011600. Its totient is φ = 780689788176.

The previous prime is 1821609505721. The next prime is 1821609505783. The reversal of 1821609505772 is 2775059061281.

1821609505772 is an admirable number.

It is a super-2 number, since 2×1821609505772² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32528741147 + ... + 32528741202.

It is an arithmetic number, because the mean of its divisors is an integer number (303601584300).

Almost surely, 2^{1821609505772} is an apocalyptic number.

It is an amenable number.

1821609505772 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

1821609505772 is a wasteful number, since it uses less digits than its factorization.

1821609505772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65057482360 (or 65057482358 counting only the distinct ones).

The product of its (nonzero) digits is 2116800, while the sum is 53.

The spelling of 1821609505772 in words is "one trillion, eight hundred twenty-one billion, six hundred nine million, five hundred five thousand, seven hundred seventy-two".