216521505966 has 16 divisors (see below), whose sum is σ = 433224306000. Its totient is φ = 72143619648.

The previous prime is 216521505943. The next prime is 216521505973. The reversal of 216521505966 is 669505125612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7538391 + ... + 7567058.

It is an arithmetic number, because the mean of its divisors is an integer number (27076519125).

Almost surely, 2^216521505966 is an apocalyptic number.

216521505966 is an abundant number, since it is smaller than the sum of its proper divisors (216702800034).

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

216521505966 is a wasteful number, since it uses less digits than its factorization.

216521505966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15107843.

The product of its (nonzero) digits is 972000, while the sum is 48.

The spelling of 216521505966 in words is "two hundred sixteen billion, five hundred twenty-one million, five hundred five thousand, nine hundred sixty-six".