261696405 has 32 divisors (see below), whose sum is σ = 448007040. Its totient is φ = 130049280.

The previous prime is 261696373. The next prime is 261696431. The reversal of 261696405 is 504696162.

It is not a de Polignac number, because 261696405 - 2⁵ = 261696373 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9859 + ... + 24911.

It is an arithmetic number, because the mean of its divisors is an integer number (14000220).

Almost surely, 2^261696405 is an apocalyptic number.

It is an amenable number.

261696405 is a deficient number, since it is larger than the sum of its proper divisors (186310635).

261696405 is a wasteful number, since it uses less digits than its factorization.

261696405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15141.

The product of its (nonzero) digits is 77760, while the sum is 39.

The square root of 261696405 is about 16177.0332570592. The cubic root of 261696405 is about 639.6355387459.

The spelling of 261696405 in words is "two hundred sixty-one million, six hundred ninety-six thousand, four hundred five".