66121247 has 8 divisors (see below), whose sum is σ = 68502240. Its totient is φ = 63747040.

The previous prime is 66121243. The next prime is 66121249. The reversal of 66121247 is 74212166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66121247 - 2² = 66121243 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66121243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26078 + ... + 28500.

It is an arithmetic number, because the mean of its divisors is an integer number (8562780).

Almost surely, 2^66121247 is an apocalyptic number.

66121247 is a deficient number, since it is larger than the sum of its proper divisors (2380993).

66121247 is a wasteful number, since it uses less digits than its factorization.

66121247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3393.

The product of its digits is 4032, while the sum is 29.

The square root of 66121247 is about 8131.4972176101. The cubic root of 66121247 is about 404.3713194795.

The spelling of 66121247 in words is "sixty-six million, one hundred twenty-one thousand, two hundred forty-seven".