166561087 has 64 divisors (see below), whose sum is σ = 239016960. Its totient is φ = 111974400.

The previous prime is 166561081. The next prime is 166561099. The reversal of 166561087 is 780165661.

166561087 = T₁₈₈ + T₁₈₉ + ... + T₁₀₀₁.

It is a cyclic number.

It is not a de Polignac number, because 166561087 - 2¹⁵ = 166528319 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166561081) 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 in 63 ways as a sum of consecutive naturals, for example, 920137 + ... + 920317.

It is an arithmetic number, because the mean of its divisors is an integer number (3734640).

Almost surely, 2^166561087 is an apocalyptic number.

166561087 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

166561087 is a deficient number, since it is larger than the sum of its proper divisors (72455873).

166561087 is a wasteful number, since it uses less digits than its factorization.

166561087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272.

The product of its (nonzero) digits is 60480, while the sum is 40.

The square root of 166561087 is about 12905.8547566599. The cubic root of 166561087 is about 550.2049781432.

The spelling of 166561087 in words is "one hundred sixty-six million, five hundred sixty-one thousand, eighty-seven".