21541911966 has 24 divisors (see below), whose sum is σ = 48179761344. Its totient is φ = 6949003680.

The previous prime is 21541911961. The next prime is 21541912001. The reversal of 21541911966 is 66911914512.

21541911966 is a `hidden beast` number, since 2 + 1 + 541 + 9 + 11 + 96 + 6 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21541911961) 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 11 ways as a sum of consecutive naturals, for example, 19302231 + ... + 19303346.

It is an arithmetic number, because the mean of its divisors is an integer number (2007490056).

Almost surely, 2^21541911966 is an apocalyptic number.

21541911966 is an abundant number, since it is smaller than the sum of its proper divisors (26637849378).

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

21541911966 is a wasteful number, since it uses less digits than its factorization.

21541911966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38605616 (or 38605613 counting only the distinct ones).

The product of its digits is 116640, while the sum is 45.

The spelling of 21541911966 in words is "twenty-one billion, five hundred forty-one million, nine hundred eleven thousand, nine hundred sixty-six".