66720215 has 8 divisors (see below), whose sum is σ = 82647168. Its totient is φ = 51654240.

The previous prime is 66720211. The next prime is 66720289. The reversal of 66720215 is 51202766.

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

It is not a de Polignac number, because 66720215 - 2² = 66720211 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66720211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 215072 + ... + 215381.

It is an arithmetic number, because the mean of its divisors is an integer number (10330896).

Almost surely, 2^66720215 is an apocalyptic number.

66720215 is a deficient number, since it is larger than the sum of its proper divisors (15926953).

66720215 is a wasteful number, since it uses less digits than its factorization.

66720215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430489.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 66720215 is about 8168.2443033984. The cubic root of 66720215 is about 405.5886679107.

The spelling of 66720215 in words is "sixty-six million, seven hundred twenty thousand, two hundred fifteen".