66551723431 has 2 divisors, whose sum is σ = 66551723432. Its totient is φ = 66551723430.

The previous prime is 66551723417. The next prime is 66551723443. The reversal of 66551723431 is 13432715566.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66551723431 - 2¹³ = 66551715239 is a prime.

It is a super-2 number, since 2×66551723431² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66551723461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33275861715 + 33275861716.

It is an arithmetic number, because the mean of its divisors is an integer number (33275861716).

Almost surely, 2^66551723431 is an apocalyptic number.

66551723431 is a deficient number, since it is larger than the sum of its proper divisors (1).

66551723431 is an equidigital number, since it uses as much as digits as its factorization.

66551723431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 453600, while the sum is 43.

The spelling of 66551723431 in words is "sixty-six billion, five hundred fifty-one million, seven hundred twenty-three thousand, four hundred thirty-one".