261441631 has 16 divisors (see below), whose sum is σ = 297363456. Its totient is φ = 227700000.

The previous prime is 261441619. The next prime is 261441637. The reversal of 261441631 is 136144162.

It is not a de Polignac number, because 261441631 - 2¹³ = 261433439 is a prime.

It is a super-2 number, since 2×261441631² = 136703452839880322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261441631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261441637) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30646 + ... + 38236.

It is an arithmetic number, because the mean of its divisors is an integer number (18585216).

Almost surely, 2^261441631 is an apocalyptic number.

261441631 is a deficient number, since it is larger than the sum of its proper divisors (35921825).

261441631 is a wasteful number, since it uses less digits than its factorization.

261441631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7734.

The product of its digits is 3456, while the sum is 28.

The square root of 261441631 is about 16169.1567807354. The cubic root of 261441631 is about 639.4278993921.

Adding to 261441631 its reverse (136144162), we get a palindrome (397585793).

The spelling of 261441631 in words is "two hundred sixty-one million, four hundred forty-one thousand, six hundred thirty-one".