166451413781 has 2 divisors, whose sum is σ = 166451413782. Its totient is φ = 166451413780.

The previous prime is 166451413697. The next prime is 166451413823. The reversal of 166451413781 is 187314154661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 124111767025 + 42339646756 = 352295^2 + 205766^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166451413781 is a prime.

It is a super-2 number, since 2×166451413781² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166451473781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83225706890 + 83225706891.

It is an arithmetic number, because the mean of its divisors is an integer number (83225706891).

Almost surely, 2^166451413781 is an apocalyptic number.

It is an amenable number.

166451413781 is a deficient number, since it is larger than the sum of its proper divisors (1).

166451413781 is an equidigital number, since it uses as much as digits as its factorization.

166451413781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 483840, while the sum is 47.

The spelling of 166451413781 in words is "one hundred sixty-six billion, four hundred fifty-one million, four hundred thirteen thousand, seven hundred eighty-one".