105664653721 has 27 divisors (see below), whose sum is σ = 120405013183. Its totient is φ = 92655387440.

The previous prime is 105664653707. The next prime is 105664653767. The reversal of 105664653721 is 127356466501.

The square root of 105664653721 is 325061.

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

It can be written as a sum of positive squares in only one way, i.e., 55407981321 + 50256672400 = 235389^2 + 224180^2 .

It is not a de Polignac number, because 105664653721 - 2¹⁹ = 105664129433 is a prime.

It is a super-2 number, since 2×105664653721² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (105664653701) 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 26 ways as a sum of consecutive naturals, for example, 103693950 + ... + 103694968.

Almost surely, 2^105664653721 is an apocalyptic number.

105664653721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

105664653721 is the 325061-st square number.

105664653721 is the 162531-st centered octagonal number.

It is an amenable number.

105664653721 is a deficient number, since it is larger than the sum of its proper divisors (14740359462).

105664653721 is an frugal number, since it uses more digits than its factorization.

105664653721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2118 (or 1059 counting only the distinct ones).

The product of its (nonzero) digits is 907200, while the sum is 46.

The spelling of 105664653721 in words is "one hundred five billion, six hundred sixty-four million, six hundred fifty-three thousand, seven hundred twenty-one".