21786609471640 has 64 divisors (see below), whose sum is σ = 52792901300160. Its totient is φ = 8043940569600.

The previous prime is 21786609471631. The next prime is 21786609471647. The reversal of 21786609471640 is 4617490668712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21786609471647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11360365 + ... + 13138915.

It is an arithmetic number, because the mean of its divisors is an integer number (824889082815).

Almost surely, 2^{21786609471640} is an apocalyptic number.

21786609471640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21786609471640 is an abundant number, since it is smaller than the sum of its proper divisors (31006291828520).

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

21786609471640 is a wasteful number, since it uses less digits than its factorization.

21786609471640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1802132 (or 1802128 counting only the distinct ones).

The product of its (nonzero) digits is 24385536, while the sum is 61.

The spelling of 21786609471640 in words is "twenty-one trillion, seven hundred eighty-six billion, six hundred nine million, four hundred seventy-one thousand, six hundred forty".