21506066166452 has 12 divisors (see below), whose sum is σ = 43012132332960. Its totient is φ = 9216885499896.

The previous prime is 21506066166451. The next prime is 21506066166461. The reversal of 21506066166452 is 25466166060512.

21506066166452 is an admirable number.

It is a super-2 number, since 2×21506066166452² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21506066166452.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21506066166451) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 384036895802 + ... + 384036895857.

It is an arithmetic number, because the mean of its divisors is an integer number (3584344361080).

Almost surely, 2^{21506066166452} is an apocalyptic number.

It is an amenable number.

21506066166452 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.

21506066166452 is a wasteful number, since it uses less digits than its factorization.

21506066166452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 768073791670 (or 768073791668 counting only the distinct ones).

The product of its (nonzero) digits is 3110400, while the sum is 50.

The spelling of 21506066166452 in words is "twenty-one trillion, five hundred six billion, sixty-six million, one hundred sixty-six thousand, four hundred fifty-two".