166521437 has 2 divisors, whose sum is σ = 166521438. Its totient is φ = 166521436.

The previous prime is 166521431. The next prime is 166521457. The reversal of 166521437 is 734125661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 158030041 + 8491396 = 12571^2 + 2914^2 .

It is a cyclic number.

It is not a de Polignac number, because 166521437 - 2¹⁰ = 166520413 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 166521397 and 166521406.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166521431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83260718 + 83260719.

It is an arithmetic number, because the mean of its divisors is an integer number (83260719).

Almost surely, 2^166521437 is an apocalyptic number.

It is an amenable number.

166521437 is a deficient number, since it is larger than the sum of its proper divisors (1).

166521437 is an equidigital number, since it uses as much as digits as its factorization.

166521437 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30240, while the sum is 35.

The square root of 166521437 is about 12904.3185407057. The cubic root of 166521437 is about 550.1613157666.

The spelling of 166521437 in words is "one hundred sixty-six million, five hundred twenty-one thousand, four hundred thirty-seven".