261523543 has 16 divisors (see below), whose sum is σ = 284991840. Its totient is φ = 239155200.

The previous prime is 261523541. The next prime is 261523567. The reversal of 261523543 is 345325162.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 261523543 - 2¹ = 261523541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261523541) 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, 73833 + ... + 77293.

It is an arithmetic number, because the mean of its divisors is an integer number (17811990).

Almost surely, 2^261523543 is an apocalyptic number.

261523543 is a deficient number, since it is larger than the sum of its proper divisors (23468297).

261523543 is a wasteful number, since it uses less digits than its factorization.

261523543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3618.

The product of its digits is 21600, while the sum is 31.

The square root of 261523543 is about 16171.6895530430. The cubic root of 261523543 is about 639.4946719113.

The spelling of 261523543 in words is "two hundred sixty-one million, five hundred twenty-three thousand, five hundred forty-three".