261423246745663 has 4 divisors (see below), whose sum is σ = 264732401767840. Its totient is φ = 258114091723488.

The previous prime is 261423246745621. The next prime is 261423246745711. The reversal of 261423246745663 is 366547642324162.

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 261423246745663 - 2⁴⁵ = 226238874656831 is a prime.

It is a super-2 number, since 2×261423246745663² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261423246745163) 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, 1654577510970 + ... + 1654577511127.

It is an arithmetic number, because the mean of its divisors is an integer number (66183100441960).

Almost surely, 2^{261423246745663} is an apocalyptic number.

261423246745663 is a deficient number, since it is larger than the sum of its proper divisors (3309155022177).

261423246745663 is an equidigital number, since it uses as much as digits as its factorization.

261423246745663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3309155022176.

The product of its digits is 209018880, while the sum is 61.

The spelling of 261423246745663 in words is "two hundred sixty-one trillion, four hundred twenty-three billion, two hundred forty-six million, seven hundred forty-five thousand, six hundred sixty-three".