261437009 has 4 divisors (see below), whose sum is σ = 261915504. Its totient is φ = 260958516.

The previous prime is 261437003. The next prime is 261437051. The reversal of 261437009 is 900734162.

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, and also an emirpimes, since its reverse is a distinct semiprime: 900734162 = 2 ⋅450367081.

It is a cyclic number.

It is not a de Polignac number, because 261437009 - 2⁸ = 261436753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261437003) 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, 238427 + ... + 239520.

It is an arithmetic number, because the mean of its divisors is an integer number (65478876).

Almost surely, 2^261437009 is an apocalyptic number.

It is an amenable number.

261437009 is a deficient number, since it is larger than the sum of its proper divisors (478495).

261437009 is an equidigital number, since it uses as much as digits as its factorization.

261437009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 478494.

The product of its (nonzero) digits is 9072, while the sum is 32.

The square root of 261437009 is about 16169.0138536647. The cubic root of 261437009 is about 639.4241312429.

The spelling of 261437009 in words is "two hundred sixty-one million, four hundred thirty-seven thousand, nine".