261543746053619 has 4 divisors (see below), whose sum is σ = 262898894997096. Its totient is φ = 260188597110144.

The previous prime is 261543746053613. The next prime is 261543746053627. The reversal of 261543746053619 is 916350647345162.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261543746053619 is a prime.

It is a super-2 number, since 2×261543746053619² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261543746053613) 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, 677574471449 + ... + 677574471834.

It is an arithmetic number, because the mean of its divisors is an integer number (65724723749274).

Almost surely, 2^{261543746053619} is an apocalyptic number.

261543746053619 is a deficient number, since it is larger than the sum of its proper divisors (1355148943477).

261543746053619 is a wasteful number, since it uses less digits than its factorization.

261543746053619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1355148943476.

The product of its (nonzero) digits is 97977600, while the sum is 62.

The spelling of 261543746053619 in words is "two hundred sixty-one trillion, five hundred forty-three billion, seven hundred forty-six million, fifty-three thousand, six hundred nineteen".