261080399 has 4 divisors (see below), whose sum is σ = 268136664. Its totient is φ = 254024136.

The previous prime is 261080353. The next prime is 261080423. The reversal of 261080399 is 993080162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 993080162 = 2 ⋅496540081.

It is a cyclic number.

It is not a de Polignac number, because 261080399 - 2¹⁶ = 261014863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261080329) 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, 3528077 + ... + 3528150.

It is an arithmetic number, because the mean of its divisors is an integer number (67034166).

Almost surely, 2^261080399 is an apocalyptic number.

261080399 is a deficient number, since it is larger than the sum of its proper divisors (7056265).

261080399 is an equidigital number, since it uses as much as digits as its factorization.

261080399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7056264.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 261080399 is about 16157.9825163911. The cubic root of 261080399 is about 639.1332660268.

The spelling of 261080399 in words is "two hundred sixty-one million, eighty thousand, three hundred ninety-nine".