261338137 has 4 divisors (see below), whose sum is σ = 261421776. Its totient is φ = 261254500.

The previous prime is 261338113. The next prime is 261338171. The reversal of 261338137 is 731833162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 261338137 - 2⁷ = 261338009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261338197) 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, 36943 + ... + 43444.

It is an arithmetic number, because the mean of its divisors is an integer number (65355444).

Almost surely, 2^261338137 is an apocalyptic number.

It is an amenable number.

261338137 is a deficient number, since it is larger than the sum of its proper divisors (83639).

261338137 is an equidigital number, since it uses as much as digits as its factorization.

261338137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83638.

The product of its digits is 18144, while the sum is 34.

The square root of 261338137 is about 16165.9561115327. The cubic root of 261338137 is about 639.3435138450.

The spelling of 261338137 in words is "two hundred sixty-one million, three hundred thirty-eight thousand, one hundred thirty-seven".