166021206849 has 21 divisors (see below), whose sum is σ = 248934436689. Its totient is φ = 110673470340.

The previous prime is 166021206823. The next prime is 166021206881. The reversal of 166021206849 is 948602120661.

The square root of 166021206849 is 407457.

It is a perfect power (a square), and thus also a powerful number.

166021206849 is a `hidden beast` number, since 16 + 602 + 1 + 20 + 6 + 8 + 4 + 9 = 666.

It is not a de Polignac number, because 166021206849 - 2⁷ = 166021206721 is a prime.

It is a super-2 number, since 2×166021206849² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (166021202849) 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 20 ways as a sum of consecutive naturals, for example, 10993794 + ... + 11008884.

Almost surely, 2^166021206849 is an apocalyptic number.

166021206849 is the 407457-th square number.

166021206849 is the 203729-th centered octagonal number.

It is an amenable number.

166021206849 is a deficient number, since it is larger than the sum of its proper divisors (82913229840).

166021206849 is an frugal number, since it uses more digits than its factorization.

166021206849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30200 (or 15094 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The spelling of 166021206849 in words is "one hundred sixty-six billion, twenty-one million, two hundred six thousand, eight hundred forty-nine".