261545406626542 has 16 divisors (see below), whose sum is σ = 392547204620064. Its totient is φ = 130696339860000.

The previous prime is 261545406626527. The next prime is 261545406626561. The reversal of 261545406626542 is 245626604545162.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 442026292 + ... + 442617592.

It is an arithmetic number, because the mean of its divisors is an integer number (24534200288754).

Almost surely, 2^{261545406626542} is an apocalyptic number.

261545406626542 is a deficient number, since it is larger than the sum of its proper divisors (131001797993522).

261545406626542 is a wasteful number, since it uses less digits than its factorization.

261545406626542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 720075.

The product of its (nonzero) digits is 82944000, while the sum is 58.

The spelling of 261545406626542 in words is "two hundred sixty-one trillion, five hundred forty-five billion, four hundred six million, six hundred twenty-six thousand, five hundred forty-two".