66220615 has 4 divisors (see below), whose sum is σ = 79464744. Its totient is φ = 52976488.

The previous prime is 66220613. The next prime is 66220711. The reversal of 66220615 is 51602266.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 51602266 = 2 ⋅25801133.

It is a cyclic number.

It is not a de Polignac number, because 66220615 - 2¹ = 66220613 is a prime.

It is a super-3 number, since 3×66220615³ (a number of 24 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66220613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6622057 + ... + 6622066.

It is an arithmetic number, because the mean of its divisors is an integer number (19866186).

Almost surely, 2^66220615 is an apocalyptic number.

66220615 is a deficient number, since it is larger than the sum of its proper divisors (13244129).

66220615 is a wasteful number, since it uses less digits than its factorization.

66220615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13244128.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 66220615 is about 8137.6049916422. The cubic root of 66220615 is about 404.5737831826.

The spelling of 66220615 in words is "sixty-six million, two hundred twenty thousand, six hundred fifteen".