261631210 has 16 divisors (see below), whose sum is σ = 491412096. Its totient is φ = 100102288.

The previous prime is 261631199. The next prime is 261631211. The reversal of 261631210 is 12136162.

It is not an unprimeable number, because it can be changed into a prime (261631211) 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, 568534 + ... + 568993.

It is an arithmetic number, because the mean of its divisors is an integer number (30713256).

Almost surely, 2^261631210 is an apocalyptic number.

261631210 is a deficient number, since it is larger than the sum of its proper divisors (229780886).

261631210 is a wasteful number, since it uses less digits than its factorization.

261631210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1137557.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 261631210 is about 16175.0180834520. The cubic root of 261631210 is about 639.5824180285.

Adding to 261631210 its reverse (12136162), we get a palindrome (273767372).

The spelling of 261631210 in words is "two hundred sixty-one million, six hundred thirty-one thousand, two hundred ten".