66275991 has 24 divisors (see below), whose sum is σ = 101724480. Its totient is φ = 41501376.

The previous prime is 66275987. The next prime is 66275999. The reversal of 66275991 is 19957266.

It is a happy number.

It is not a de Polignac number, because 66275991 - 2² = 66275987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66275999) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6226 + ... + 13088.

It is an arithmetic number, because the mean of its divisors is an integer number (4238520).

Almost surely, 2^66275991 is an apocalyptic number.

66275991 is a deficient number, since it is larger than the sum of its proper divisors (35448489).

66275991 is a wasteful number, since it uses less digits than its factorization.

66275991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6935 (or 6932 counting only the distinct ones).

The product of its digits is 204120, while the sum is 45.

The square root of 66275991 is about 8141.0067559240. The cubic root of 66275991 is about 404.6865246897.

The spelling of 66275991 in words is "sixty-six million, two hundred seventy-five thousand, nine hundred ninety-one".