66811725 has 18 divisors (see below), whose sum is σ = 119667626. Its totient is φ = 35632800.

The previous prime is 66811709. The next prime is 66811729. The reversal of 66811725 is 52711866.

It can be written as a sum of positive squares in 3 ways, for example, as 8838729 + 57972996 = 2973^2 + 7614^2 .

It is not a de Polignac number, because 66811725 - 2⁴ = 66811709 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66811725.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66811729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 148246 + ... + 148695.

Almost surely, 2^66811725 is an apocalyptic number.

It is an amenable number.

66811725 is a deficient number, since it is larger than the sum of its proper divisors (52855901).

66811725 is a wasteful number, since it uses less digits than its factorization.

66811725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296957 (or 296949 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 66811725 is about 8173.8439549578. The cubic root of 66811725 is about 405.7740113552.

The spelling of 66811725 in words is "sixty-six million, eight hundred eleven thousand, seven hundred twenty-five".