261690198 has 32 divisors (see below), whose sum is σ = 652527360. Its totient is φ = 67971360.

The previous prime is 261690151. The next prime is 261690199. The reversal of 261690198 is 891096162.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261690199) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 282753 + ... + 283676.

It is an arithmetic number, because the mean of its divisors is an integer number (20391480).

Almost surely, 2^261690198 is an apocalyptic number.

261690198 is an abundant number, since it is smaller than the sum of its proper divisors (390837162).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261690198 is a wasteful number, since it uses less digits than its factorization.

261690198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 566452.

The product of its (nonzero) digits is 46656, while the sum is 42.

The square root of 261690198 is about 16176.8414098674. The cubic root of 261690198 is about 639.6304816784.

The spelling of 261690198 in words is "two hundred sixty-one million, six hundred ninety thousand, one hundred ninety-eight".