261640743 has 32 divisors (see below), whose sum is σ = 438144000. Its totient is φ = 138001248.

The previous prime is 261640741. The next prime is 261640759. The reversal of 261640743 is 347046162.

It is a happy number.

261640743 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 261640743 - 2¹ = 261640741 is a prime.

It is a super-3 number, since 3×261640743³ (a number of 26 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261640741) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3598 + ... + 23156.

It is an arithmetic number, because the mean of its divisors is an integer number (13692000).

Almost surely, 2^261640743 is an apocalyptic number.

261640743 is a deficient number, since it is larger than the sum of its proper divisors (176503257).

261640743 is a wasteful number, since it uses less digits than its factorization.

261640743 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19596 (or 19582 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 33.

The square root of 261640743 is about 16175.3127635913. The cubic root of 261640743 is about 639.5901860430.

The spelling of 261640743 in words is "two hundred sixty-one million, six hundred forty thousand, seven hundred forty-three".