66566610225 has 18 divisors (see below), whose sum is σ = 119228195606. Its totient is φ = 35502192000.

The previous prime is 66566610223. The next prime is 66566610239. The reversal of 66566610225 is 52201666566.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 9604196001 + 56962414224 = 98001^2 + 238668^2 .

It is not a de Polignac number, because 66566610225 - 2¹ = 66566610223 is a prime.

It is a super-2 number, since 2×66566610225² (a number of 22 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66566610223) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 147925576 + ... + 147926025.

Almost surely, 2^66566610225 is an apocalyptic number.

It is an amenable number.

66566610225 is a deficient number, since it is larger than the sum of its proper divisors (52661585381).

66566610225 is a wasteful number, since it uses less digits than its factorization.

66566610225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295851617 (or 295851609 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 45.

The spelling of 66566610225 in words is "sixty-six billion, five hundred sixty-six million, six hundred ten thousand, two hundred twenty-five".