166015231552421 has 2 divisors, whose sum is σ = 166015231552422. Its totient is φ = 166015231552420.

The previous prime is 166015231552381. The next prime is 166015231552477. The reversal of 166015231552421 is 124255132510661.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 114604754140321 + 51410477412100 = 10705361^2 + 7170110^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166015231552421 is a prime.

It is a super-2 number, since 2×166015231552421² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166015231552021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83007615776210 + 83007615776211.

It is an arithmetic number, because the mean of its divisors is an integer number (83007615776211).

Almost surely, 2^{166015231552421} is an apocalyptic number.

It is an amenable number.

166015231552421 is a deficient number, since it is larger than the sum of its proper divisors (1).

166015231552421 is an equidigital number, since it uses as much as digits as its factorization.

166015231552421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432000, while the sum is 44.

The spelling of 166015231552421 in words is "one hundred sixty-six trillion, fifteen billion, two hundred thirty-one million, five hundred fifty-two thousand, four hundred twenty-one".