21661150550 has 24 divisors (see below), whose sum is σ = 43388952096. Its totient is φ = 7997963040.

The previous prime is 21661150549. The next prime is 21661150561. The reversal of 21661150550 is 5505116612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16661774 + ... + 16663073.

It is an arithmetic number, because the mean of its divisors is an integer number (1807873004).

Almost surely, 2^21661150550 is an apocalyptic number.

21661150550 is an abundant number, since it is smaller than the sum of its proper divisors (21727801546).

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

21661150550 is a wasteful number, since it uses less digits than its factorization.

21661150550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33324872 (or 33324867 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 32.

The spelling of 21661150550 in words is "twenty-one billion, six hundred sixty-one million, one hundred fifty thousand, five hundred fifty".