66608621531 has 2 divisors, whose sum is σ = 66608621532. Its totient is φ = 66608621530.

The previous prime is 66608621477. The next prime is 66608621557. The reversal of 66608621531 is 13512680666.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66608621531 is a prime.

It is a super-2 number, since 2×66608621531² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66608621561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33304310765 + 33304310766.

It is an arithmetic number, because the mean of its divisors is an integer number (33304310766).

Almost surely, 2^66608621531 is an apocalyptic number.

66608621531 is a deficient number, since it is larger than the sum of its proper divisors (1).

66608621531 is an equidigital number, since it uses as much as digits as its factorization.

66608621531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 311040, while the sum is 44.

The spelling of 66608621531 in words is "sixty-six billion, six hundred eight million, six hundred twenty-one thousand, five hundred thirty-one".