261562731506542 has 4 divisors (see below), whose sum is σ = 392344097259816. Its totient is φ = 130781365753270.

The previous prime is 261562731506537. The next prime is 261562731506551. The reversal of 261562731506542 is 245605137265162.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65390682876634 + ... + 65390682876637.

It is an arithmetic number, because the mean of its divisors is an integer number (98086024314954).

Almost surely, 2^{261562731506542} is an apocalyptic number.

261562731506542 is a deficient number, since it is larger than the sum of its proper divisors (130781365753274).

261562731506542 is a wasteful number, since it uses less digits than its factorization.

261562731506542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130781365753273.

The product of its (nonzero) digits is 18144000, while the sum is 55.

The spelling of 261562731506542 in words is "two hundred sixty-one trillion, five hundred sixty-two billion, seven hundred thirty-one million, five hundred six thousand, five hundred forty-two".