66611215 has 16 divisors (see below), whose sum is σ = 87607296. Its totient is φ = 48218400.

The previous prime is 66611201. The next prime is 66611221. The reversal of 66611215 is 51211666.

It is not a de Polignac number, because 66611215 - 2⁷ = 66611087 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9550 + ... + 14980.

It is an arithmetic number, because the mean of its divisors is an integer number (5475456).

Almost surely, 2^66611215 is an apocalyptic number.

66611215 is a deficient number, since it is larger than the sum of its proper divisors (20996081).

66611215 is a wasteful number, since it uses less digits than its factorization.

66611215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5670.

The product of its digits is 2160, while the sum is 28.

The square root of 66611215 is about 8161.5693956493. The cubic root of 66611215 is about 405.3676791078.

It can be divided in two parts, 666 and 11215, that added together give a square (11881 = 109²).

The spelling of 66611215 in words is "sixty-six million, six hundred eleven thousand, two hundred fifteen".