261251090 has 16 divisors (see below), whose sum is σ = 477271872. Its totient is φ = 102940464.

The previous prime is 261251077. The next prime is 261251119. The reversal of 261251090 is 90152162.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 194294 + ... + 195633.

It is an arithmetic number, because the mean of its divisors is an integer number (29829492).

Almost surely, 2^261251090 is an apocalyptic number.

261251090 is a deficient number, since it is larger than the sum of its proper divisors (216020782).

261251090 is a wasteful number, since it uses less digits than its factorization.

261251090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390001.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 261251090 is about 16163.2635937177. The cubic root of 261251090 is about 639.2725213808.

The spelling of 261251090 in words is "two hundred sixty-one million, two hundred fifty-one thousand, ninety".