66219995 has 4 divisors (see below), whose sum is σ = 79464000. Its totient is φ = 52975992.

The previous prime is 66219991. The next prime is 66220003. The reversal of 66219995 is 59991266.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66219995 - 2² = 66219991 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66219991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6621995 + ... + 6622004.

It is an arithmetic number, because the mean of its divisors is an integer number (19866000).

Almost surely, 2^66219995 is an apocalyptic number.

66219995 is a deficient number, since it is larger than the sum of its proper divisors (13244005).

66219995 is a wasteful number, since it uses less digits than its factorization.

66219995 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13244004.

The product of its digits is 262440, while the sum is 47.

The square root of 66219995 is about 8137.5668968064. The cubic root of 66219995 is about 404.5725205520.

The spelling of 66219995 in words is "sixty-six million, two hundred nineteen thousand, nine hundred ninety-five".