66540511504565 has 16 divisors (see below), whose sum is σ = 92108414328192. Its totient is φ = 45201351470784.

The previous prime is 66540511504477. The next prime is 66540511504661. The reversal of 66540511504565 is 56540511504566.

It is a cyclic number.

It is not a de Polignac number, because 66540511504565 - 2³⁸ = 66265633597621 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, 8883909674 + ... + 8883917163.

It is an arithmetic number, because the mean of its divisors is an integer number (5756775895512).

Almost surely, 2^{66540511504565} is an apocalyptic number.

It is an amenable number.

66540511504565 is a deficient number, since it is larger than the sum of its proper divisors (25567902823627).

66540511504565 is a wasteful number, since it uses less digits than its factorization.

66540511504565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17767826956.

The product of its (nonzero) digits is 10800000, while the sum is 53.

Subtracting from 66540511504565 its reverse (56540511504566), we obtain a palindrome (9999999999999).

The spelling of 66540511504565 in words is "sixty-six trillion, five hundred forty billion, five hundred eleven million, five hundred four thousand, five hundred sixty-five".