66110721 has 16 divisors (see below), whose sum is σ = 89107200. Its totient is φ = 43597440.

The previous prime is 66110711. The next prime is 66110729. The reversal of 66110721 is 12701166.

It is not a de Polignac number, because 66110721 - 2¹⁷ = 65979649 is a prime.

It is a super-2 number, since 2×66110721² = 8741254862279682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66110691 and 66110700.

It is not an unprimeable number, because it can be changed into a prime (66110729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 189255 + ... + 189603.

It is an arithmetic number, because the mean of its divisors is an integer number (5569200).

Almost surely, 2^66110721 is an apocalyptic number.

It is an amenable number.

66110721 is a deficient number, since it is larger than the sum of its proper divisors (22996479).

66110721 is a wasteful number, since it uses less digits than its factorization.

66110721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 856.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 66110721 is about 8130.8499555705. The cubic root of 66110721 is about 404.3498607271.

Adding to 66110721 its reverse (12701166), we get a palindrome (78811887).

The spelling of 66110721 in words is "sixty-six million, one hundred ten thousand, seven hundred twenty-one".