261535166021242 has 8 divisors (see below), whose sum is σ = 392305711613076. Its totient is φ = 130766595483552.

The previous prime is 261535166021209. The next prime is 261535166021249. The reversal of 261535166021242 is 242120661535162.

It can be written as a sum of positive squares in 2 ways, for example, as 197644543249321 + 63890622771921 = 14058611^2 + 7993161^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 261535166021192 and 261535166021201.

It is not an unprimeable number, because it can be changed into a prime (261535166021249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 493432443 + ... + 493962190.

Almost surely, 2^{261535166021242} is an apocalyptic number.

261535166021242 is a deficient number, since it is larger than the sum of its proper divisors (130770545591834).

261535166021242 is a wasteful number, since it uses less digits than its factorization.

261535166021242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 987527072.

The product of its (nonzero) digits is 1036800, while the sum is 46.

The spelling of 261535166021242 in words is "two hundred sixty-one trillion, five hundred thirty-five billion, one hundred sixty-six million, twenty-one thousand, two hundred forty-two".