261994965 has 16 divisors (see below), whose sum is σ = 430522368. Its totient is φ = 135953856.

The previous prime is 261994951. The next prime is 261994979. The reversal of 261994965 is 569499162.

It is an interprime number because it is at equal distance from previous prime (261994951) and next prime (261994979).

It is not a de Polignac number, because 261994965 - 2¹⁴ = 261978581 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 235477 + ... + 236586.

It is an arithmetic number, because the mean of its divisors is an integer number (26907648).

Almost surely, 2^261994965 is an apocalyptic number.

It is an amenable number.

261994965 is a deficient number, since it is larger than the sum of its proper divisors (168527403).

261994965 is a wasteful number, since it uses less digits than its factorization.

261994965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 472108.

The product of its digits is 1049760, while the sum is 51.

The square root of 261994965 is about 16186.2585238220. The cubic root of 261994965 is about 639.8786920148.

It can be divided in two parts, 26 and 1994965, that added together give a palindrome (1994991).

The spelling of 261994965 in words is "two hundred sixty-one million, nine hundred ninety-four thousand, nine hundred sixty-five".