221561166016611 has 12 divisors (see below), whose sum is σ = 338858253907992. Its totient is φ = 139018770833856.

The previous prime is 221561166016583. The next prime is 221561166016657. The reversal of 221561166016611 is 116610661165122.

It is a happy number.

221561166016611 is a `hidden beast` number, since 2 + 2 + 1 + 5 + 6 + 1 + 16 + 6 + 0 + 16 + 611 = 666.

It is not a de Polignac number, because 221561166016611 - 2¹⁹ = 221561165492323 is a prime.

It is a super-2 number, since 2×221561166016611² (a number of 29 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (221561166012611) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 724056097941 + ... + 724056098246.

It is an arithmetic number, because the mean of its divisors is an integer number (28238187825666).

Almost surely, 2^{221561166016611} is an apocalyptic number.

221561166016611 is a deficient number, since it is larger than the sum of its proper divisors (117297087891381).

221561166016611 is a wasteful number, since it uses less digits than its factorization.

221561166016611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1448112196210 (or 1448112196207 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The spelling of 221561166016611 in words is "two hundred twenty-one trillion, five hundred sixty-one billion, one hundred sixty-six million, sixteen thousand, six hundred eleven".