261421166 has 32 divisors (see below), whose sum is σ = 414602496. Its totient is φ = 123480000.

The previous prime is 261421163. The next prime is 261421183. The reversal of 261421166 is 661124162.

It is a super-3 number, since 3×261421166³ (a number of 26 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261421163) 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 15 ways as a sum of consecutive naturals, for example, 532181 + ... + 532671.

It is an arithmetic number, because the mean of its divisors is an integer number (12956328).

Almost surely, 2^261421166 is an apocalyptic number.

261421166 is a deficient number, since it is larger than the sum of its proper divisors (153181330).

261421166 is a wasteful number, since it uses less digits than its factorization.

261421166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 728.

The product of its digits is 3456, while the sum is 29.

The square root of 261421166 is about 16168.5239276812. The cubic root of 261421166 is about 639.4112146820.

The spelling of 261421166 in words is "two hundred sixty-one million, four hundred twenty-one thousand, one hundred sixty-six".