66211009225 has 27 divisors (see below), whose sum is σ = 83766235189. Its totient is φ = 51915874400.

The previous prime is 66211009211. The next prime is 66211009231. The reversal of 66211009225 is 52290011266.

It is a happy number.

The square root of 66211009225 is 257315.

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

It can be written as a sum of positive squares in 4 ways, for example, as 498762889 + 65712246336 = 22333^2 + 256344^2 .

It is not a de Polignac number, because 66211009225 - 2⁹ = 66211008713 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 68187990 + ... + 68188960.

Almost surely, 2^66211009225 is an apocalyptic number.

66211009225 is the 257315-th square number.

66211009225 is the 128658-th centered octagonal number.

It is an amenable number.

66211009225 is a deficient number, since it is larger than the sum of its proper divisors (17555225964).

66211009225 is an frugal number, since it uses more digits than its factorization.

66211009225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2058 (or 1029 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 34.

The spelling of 66211009225 in words is "sixty-six billion, two hundred eleven million, nine thousand, two hundred twenty-five".