66615565 has 16 divisors (see below), whose sum is σ = 81607680. Its totient is φ = 52191360.

The previous prime is 66615547. The next prime is 66615583. The reversal of 66615565 is 56551666.

It is an interprime number because it is at equal distance from previous prime (66615547) and next prime (66615583).

It is not a de Polignac number, because 66615565 - 2¹¹ = 66613517 is a prime.

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, 53500 + ... + 54730.

It is an arithmetic number, because the mean of its divisors is an integer number (5100480).

Almost surely, 2^66615565 is an apocalyptic number.

It is an amenable number.

66615565 is a deficient number, since it is larger than the sum of its proper divisors (14992115).

66615565 is a wasteful number, since it uses less digits than its factorization.

66615565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1452.

The product of its digits is 162000, while the sum is 40.

The square root of 66615565 is about 8161.8358841623. The cubic root of 66615565 is about 405.3765030024.

It can be divided in two parts, 6661556 and 5, that added together give a square (6661561 = 2581²).

The spelling of 66615565 in words is "sixty-six million, six hundred fifteen thousand, five hundred sixty-five".