21650542066 has 32 divisors (see below), whose sum is σ = 36405365760. Its totient is φ = 9596411136.

The previous prime is 21650542051. The next prime is 21650542087. The reversal of 21650542066 is 66024505612.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14895 + ... + 208621.

It is an arithmetic number, because the mean of its divisors is an integer number (1137667680).

Almost surely, 2^21650542066 is an apocalyptic number.

21650542066 is a deficient number, since it is larger than the sum of its proper divisors (14754823694).

21650542066 is a wasteful number, since it uses less digits than its factorization.

21650542066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193938.

The product of its (nonzero) digits is 86400, while the sum is 37.

The spelling of 21650542066 in words is "twenty-one billion, six hundred fifty million, five hundred forty-two thousand, sixty-six".