261432166 has 4 divisors (see below), whose sum is σ = 392148252. Its totient is φ = 130716082.

The previous prime is 261432151. The next prime is 261432179. The reversal of 261432166 is 661234162.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65358040 + ... + 65358043.

It is an arithmetic number, because the mean of its divisors is an integer number (98037063).

Almost surely, 2^261432166 is an apocalyptic number.

261432166 is a deficient number, since it is larger than the sum of its proper divisors (130716086).

261432166 is a wasteful number, since it uses less digits than its factorization.

261432166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130716085.

The product of its digits is 10368, while the sum is 31.

The square root of 261432166 is about 16168.8640912094. The cubic root of 261432166 is about 639.4201828728.

The spelling of 261432166 in words is "two hundred sixty-one million, four hundred thirty-two thousand, one hundred sixty-six".