21820134667644 has 36 divisors (see below), whose sum is σ = 55201922737416. Its totient is φ = 7267382018208.

The previous prime is 21820134667561. The next prime is 21820134667663. The reversal of 21820134667644 is 44676643102812.

21820134667644 is a `hidden beast` number, since 2 + 182 + 0 + 1 + 346 + 67 + 64 + 4 = 666.

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

It is a super-2 number, since 2×21820134667644² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 249797574 + ... + 249884909.

It is an arithmetic number, because the mean of its divisors is an integer number (1533386742706).

Almost surely, 2^{21820134667644} is an apocalyptic number.

It is an amenable number.

21820134667644 is an abundant number, since it is smaller than the sum of its proper divisors (33381788069772).

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

21820134667644 is a wasteful number, since it uses less digits than its factorization.

21820134667644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 499683706 (or 499683701 counting only the distinct ones).

The product of its (nonzero) digits is 9289728, while the sum is 54.

The spelling of 21820134667644 in words is "twenty-one trillion, eight hundred twenty billion, one hundred thirty-four million, six hundred sixty-seven thousand, six hundred forty-four".