66121225 has 6 divisors (see below), whose sum is σ = 81990350. Its totient is φ = 52896960.

The previous prime is 66121201. The next prime is 66121243. The reversal of 66121225 is 52212166.

It can be written as a sum of positive squares in 3 ways, for example, as 18386944 + 47734281 = 4288^2 + 6909^2 .

It is not a de Polignac number, because 66121225 - 2⁵ = 66121193 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25), and also a Moran number because the ratio is a prime number: 2644849 = 66121225 / (6 + 6 + 1 + 2 + 1 + 2 + 2 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 66121225.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1322400 + ... + 1322449.

Almost surely, 2^66121225 is an apocalyptic number.

It is an amenable number.

66121225 is a deficient number, since it is larger than the sum of its proper divisors (15869125).

66121225 is a wasteful number, since it uses less digits than its factorization.

66121225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2644859 (or 2644854 counting only the distinct ones).

The product of its digits is 1440, while the sum is 25.

The square root of 66121225 is about 8131.4958648455. The cubic root of 66121225 is about 404.3712746317.

The spelling of 66121225 in words is "sixty-six million, one hundred twenty-one thousand, two hundred twenty-five".