66156634663531 has 4 divisors (see below), whose sum is σ = 66156684940600. Its totient is φ = 66156584386464.

The previous prime is 66156634663529. The next prime is 66156634663571. The reversal of 66156634663531 is 13536643665166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66156634663531 - 2¹ = 66156634663529 is a prime.

It is a super-2 number, since 2×66156634663531² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66156634663531.

It is not an unprimeable number, because it can be changed into a prime (66156634663501) 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, 23110221 + ... + 25814638.

It is an arithmetic number, because the mean of its divisors is an integer number (16539171235150).

Almost surely, 2^{66156634663531} is an apocalyptic number.

66156634663531 is a deficient number, since it is larger than the sum of its proper divisors (50277069).

66156634663531 is a wasteful number, since it uses less digits than its factorization.

66156634663531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50277068.

The product of its digits is 125971200, while the sum is 61.

The spelling of 66156634663531 in words is "sixty-six trillion, one hundred fifty-six billion, six hundred thirty-four million, six hundred sixty-three thousand, five hundred thirty-one".