166051720812391 has 2 divisors, whose sum is σ = 166051720812392. Its totient is φ = 166051720812390.

The previous prime is 166051720812379. The next prime is 166051720812403. The reversal of 166051720812391 is 193218027150661.

It is a balanced prime because it is at equal distance from previous prime (166051720812379) and next prime (166051720812403).

It is a cyclic number.

It is not a de Polignac number, because 166051720812391 - 2¹³ = 166051720804199 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166051720812331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83025860406195 + 83025860406196.

It is an arithmetic number, because the mean of its divisors is an integer number (83025860406196).

Almost surely, 2^{166051720812391} is an apocalyptic number.

166051720812391 is a deficient number, since it is larger than the sum of its proper divisors (1).

166051720812391 is an equidigital number, since it uses as much as digits as its factorization.

166051720812391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1088640, while the sum is 52.

The spelling of 166051720812391 in words is "one hundred sixty-six trillion, fifty-one billion, seven hundred twenty million, eight hundred twelve thousand, three hundred ninety-one".