21166311650 has 24 divisors (see below), whose sum is σ = 42948371664. Its totient is φ = 7696840400.

The previous prime is 21166311643. The next prime is 21166311653. The reversal of 21166311650 is 5611366112.

It is not an unprimeable number, because it can be changed into a prime (21166311653) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 19241552 + ... + 19242651.

It is an arithmetic number, because the mean of its divisors is an integer number (1789515486).

Almost surely, 2^21166311650 is an apocalyptic number.

21166311650 is an abundant number, since it is smaller than the sum of its proper divisors (21782060014).

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

21166311650 is a wasteful number, since it uses less digits than its factorization.

21166311650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38484226 (or 38484221 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 32.

Adding to 21166311650 its reverse (5611366112), we get a palindrome (26777677762).

The spelling of 21166311650 in words is "twenty-one billion, one hundred sixty-six million, three hundred eleven thousand, six hundred fifty".