21046650066 has 160 divisors (see below), whose sum is σ = 54827055360. Its totient is φ = 5980334976.

The previous prime is 21046650049. The next prime is 21046650073. The reversal of 21046650066 is 66005664012.

It is a happy number.

It is a super-2 number, since 2×21046650066² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21046650066.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1397211 + ... + 1412193.

It is an arithmetic number, because the mean of its divisors is an integer number (342669096).

Almost surely, 2^21046650066 is an apocalyptic number.

21046650066 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21046650066, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27413527680).

21046650066 is an abundant number, since it is smaller than the sum of its proper divisors (33780405294).

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

21046650066 is a wasteful number, since it uses less digits than its factorization.

21046650066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15062 (or 15053 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 21046650066 in words is "twenty-one billion, forty-six million, six hundred fifty thousand, sixty-six".