261191699 has 4 divisors (see below), whose sum is σ = 261751464. Its totient is φ = 260631936.

The previous prime is 261191681. The next prime is 261191701. The reversal of 261191699 is 996191162.

261191699 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 996191162 = 2 ⋅498095581.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261191699 is a prime.

It is a super-2 number, since 2×261191699² = 136442207253013202, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261191999) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 279182 + ... + 280115.

It is an arithmetic number, because the mean of its divisors is an integer number (65437866).

Almost surely, 2^261191699 is an apocalyptic number.

261191699 is a deficient number, since it is larger than the sum of its proper divisors (559765).

261191699 is an equidigital number, since it uses as much as digits as its factorization.

261191699 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559764.

The product of its digits is 52488, while the sum is 44.

The square root of 261191699 is about 16161.4262675050. The cubic root of 261191699 is about 639.2240751246.

The spelling of 261191699 in words is "two hundred sixty-one million, one hundred ninety-one thousand, six hundred ninety-nine".