261823390 has 16 divisors (see below), whose sum is σ = 474009408. Its totient is φ = 104123296.

The previous prime is 261823381. The next prime is 261823391. The reversal of 261823390 is 93328162.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261823391) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 73942 + ... + 77401.

It is an arithmetic number, because the mean of its divisors is an integer number (29625588).

Almost surely, 2^261823390 is an apocalyptic number.

261823390 is a deficient number, since it is larger than the sum of its proper divisors (212186018).

261823390 is a wasteful number, since it uses less digits than its factorization.

261823390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151523.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 261823390 is about 16180.9576354430. The cubic root of 261823390 is about 639.7389804735.

The spelling of 261823390 in words is "two hundred sixty-one million, eight hundred twenty-three thousand, three hundred ninety".