261340564542 has 32 divisors (see below), whose sum is σ = 528693502464. Its totient is φ = 86114196000.

The previous prime is 261340564519. The next prime is 261340564559. The reversal of 261340564542 is 245465043162.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 261340564494 and 261340564503.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40663 + ... + 724109.

It is an arithmetic number, because the mean of its divisors is an integer number (16521671952).

Almost surely, 2^261340564542 is an apocalyptic number.

261340564542 is an abundant number, since it is smaller than the sum of its proper divisors (267352937922).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261340564542 is a wasteful number, since it uses less digits than its factorization.

261340564542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 684184.

The product of its (nonzero) digits is 691200, while the sum is 42.

The spelling of 261340564542 in words is "two hundred sixty-one billion, three hundred forty million, five hundred sixty-four thousand, five hundred forty-two".