170121987 has 24 divisors (see below), whose sum is σ = 284001120. Its totient is φ = 96117120.

The previous prime is 170121977. The next prime is 170122049. The reversal of 170121987 is 789121071.

It is not a de Polignac number, because 170121987 - 2¹⁴ = 170105603 is a prime.

It is not an unprimeable number, because it can be changed into a prime (170121947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9564 + ... + 20777.

It is an arithmetic number, because the mean of its divisors is an integer number (11833380).

Almost surely, 2^170121987 is an apocalyptic number.

170121987 is a deficient number, since it is larger than the sum of its proper divisors (113879133).

170121987 is a wasteful number, since it uses less digits than its factorization.

170121987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30443 (or 30440 counting only the distinct ones).

The product of its (nonzero) digits is 7056, while the sum is 36.

The square root of 170121987 is about 13043.0819594143. The cubic root of 170121987 is about 554.0982971891.

The spelling of 170121987 in words is "one hundred seventy million, one hundred twenty-one thousand, nine hundred eighty-seven".