261485640823 has 4 divisors (see below), whose sum is σ = 285257062728. Its totient is φ = 237714218920.

The previous prime is 261485640803. The next prime is 261485640833. The reversal of 261485640823 is 328046584162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261485640823 - 2¹³ = 261485632631 is a prime.

It is a super-2 number, since 2×261485640823² (a number of 24 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261485640803) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11885710936 + ... + 11885710957.

It is an arithmetic number, because the mean of its divisors is an integer number (71314265682).

Almost surely, 2^261485640823 is an apocalyptic number.

261485640823 is a deficient number, since it is larger than the sum of its proper divisors (23771421905).

261485640823 is a wasteful number, since it uses less digits than its factorization.

261485640823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23771421904.

The product of its (nonzero) digits is 2211840, while the sum is 49.

The spelling of 261485640823 in words is "two hundred sixty-one billion, four hundred eighty-five million, six hundred forty thousand, eight hundred twenty-three".