261915855 has 32 divisors (see below), whose sum is σ = 467078400. Its totient is φ = 124549632.

The previous prime is 261915853. The next prime is 261915887. The reversal of 261915855 is 558519162.

It is a happy number.

It is not a de Polignac number, because 261915855 - 2¹ = 261915853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261915851) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22185 + ... + 31874.

It is an arithmetic number, because the mean of its divisors is an integer number (14596200).

Almost surely, 2^261915855 is an apocalyptic number.

261915855 is a deficient number, since it is larger than the sum of its proper divisors (205162545).

261915855 is a wasteful number, since it uses less digits than its factorization.

261915855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54103.

The product of its digits is 108000, while the sum is 42.

The square root of 261915855 is about 16183.8145997784. The cubic root of 261915855 is about 639.8142812360.

The spelling of 261915855 in words is "two hundred sixty-one million, nine hundred fifteen thousand, eight hundred fifty-five".