21066161566650 has 48 divisors (see below), whose sum is σ = 52244457119904. Its totient is φ = 5617602607680.

The previous prime is 21066161566649. The next prime is 21066161566651. The reversal of 21066161566650 is 5666516166012.

It is an interprime number because it is at equal distance from previous prime (21066161566649) and next prime (21066161566651).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21066161566593 and 21066161566602.

It is not an unprimeable number, because it can be changed into a prime (21066161566651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24481104 + ... + 25326996.

It is an arithmetic number, because the mean of its divisors is an integer number (1088426189998).

Almost surely, 2^{21066161566650} is an apocalyptic number.

21066161566650 is an abundant number, since it is smaller than the sum of its proper divisors (31178295553254).

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

21066161566650 is a wasteful number, since it uses less digits than its factorization.

21066161566650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1011935 (or 1011930 counting only the distinct ones).

The product of its (nonzero) digits is 2332800, while the sum is 51.

The spelling of 21066161566650 in words is "twenty-one trillion, sixty-six billion, one hundred sixty-one million, five hundred sixty-six thousand, six hundred fifty".