261109197 has 16 divisors (see below), whose sum is σ = 396264960. Its totient is φ = 169826400.

The previous prime is 261109193. The next prime is 261109207. The reversal of 261109197 is 791901162.

It is not a de Polignac number, because 261109197 - 2² = 261109193 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261109193) 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, 116829 + ... + 119042.

It is an arithmetic number, because the mean of its divisors is an integer number (24766560).

Almost surely, 2^261109197 is an apocalyptic number.

261109197 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

261109197 is a deficient number, since it is larger than the sum of its proper divisors (135155763).

261109197 is a wasteful number, since it uses less digits than its factorization.

261109197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235921 (or 235915 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 36.

The square root of 261109197 is about 16158.8736302999. The cubic root of 261109197 is about 639.1567646415.

The spelling of 261109197 in words is "two hundred sixty-one million, one hundred nine thousand, one hundred ninety-seven".