66126636801 has 9 divisors (see below), whose sum is σ = 95517367491. Its totient is φ = 44083910232.

The previous prime is 66126636787. The next prime is 66126636817. The reversal of 66126636801 is 10863662166.

The square root of 66126636801 is 257151.

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

66126636801 is a `hidden beast` number, since 6 + 6 + 1 + 2 + 6 + 636 + 8 + 0 + 1 = 666.

66126636801 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 13191671025 + 52934965776 = 114855^2 + 230076^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 66126636801 - 2²⁵ = 66093082369 is a prime.

It is a super-2 number, since 2×66126636801² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66126636881) 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, 728595 + ... + 814311.

Almost surely, 2^66126636801 is an apocalyptic number.

66126636801 is the 257151-st square number.

66126636801 is the 128576-th centered octagonal number.

It is an amenable number.

66126636801 is a deficient number, since it is larger than the sum of its proper divisors (29390730690).

66126636801 is an frugal number, since it uses more digits than its factorization.

66126636801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171440 (or 85720 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The spelling of 66126636801 in words is "sixty-six billion, one hundred twenty-six million, six hundred thirty-six thousand, eight hundred one".