66145867926121 has 9 divisors (see below), whose sum is σ = 66588057333399. Its totient is φ = 65706595869000.

The previous prime is 66145867926113. The next prime is 66145867926239. The reversal of 66145867926121 is 12162976854166.

The square root of 66145867926121 is 8133011.

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., 61509339298521 + 4636528627600 = 7842789^2 + 2153260^2 .

It is not a de Polignac number, because 66145867926121 - 2³ = 66145867926113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66145867926421) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1228057731 + ... + 1228111591.

Almost surely, 2^{66145867926121} is an apocalyptic number.

66145867926121 is the 8133011-st square number.

66145867926121 is the 4066506-th centered octagonal number.

It is an amenable number.

66145867926121 is a deficient number, since it is larger than the sum of its proper divisors (442189407278).

66145867926121 is an frugal number, since it uses more digits than its factorization.

66145867926121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108024 (or 54012 counting only the distinct ones).

The product of its digits is 52254720, while the sum is 64.

The spelling of 66145867926121 in words is "sixty-six trillion, one hundred forty-five billion, eight hundred sixty-seven million, nine hundred twenty-six thousand, one hundred twenty-one".