2181826363644 has 72 divisors (see below), whose sum is σ = 5586231356160. Its totient is φ = 717909128352.

The previous prime is 2181826363603. The next prime is 2181826363741. The reversal of 2181826363644 is 4463636281812.

2181826363644 is a `hidden beast` number, since 2 + 1 + 8 + 18 + 263 + 6 + 364 + 4 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13007599 + ... + 13174265.

Almost surely, 2^{2181826363644} 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 2181826363644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2793115678080).

2181826363644 is an abundant number, since it is smaller than the sum of its proper divisors (3404404992516).

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

2181826363644 is a wasteful number, since it uses less digits than its factorization.

2181826363644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171359 (or 171354 counting only the distinct ones).

The product of its digits is 7962624, while the sum is 54.

The spelling of 2181826363644 in words is "two trillion, one hundred eighty-one billion, eight hundred twenty-six million, three hundred sixty-three thousand, six hundred forty-four".