261517426489 has 4 divisors (see below), whose sum is σ = 285291738000. Its totient is φ = 237743114980.

The previous prime is 261517426487. The next prime is 261517426603. The reversal of 261517426489 is 984624715162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 261517426489 - 2¹ = 261517426487 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261517426487) 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, 11887155739 + ... + 11887155760.

It is an arithmetic number, because the mean of its divisors is an integer number (71322934500).

Almost surely, 2^261517426489 is an apocalyptic number.

It is an amenable number.

261517426489 is a deficient number, since it is larger than the sum of its proper divisors (23774311511).

261517426489 is a wasteful number, since it uses less digits than its factorization.

261517426489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23774311510.

The product of its digits is 5806080, while the sum is 55.

The spelling of 261517426489 in words is "two hundred sixty-one billion, five hundred seventeen million, four hundred twenty-six thousand, four hundred eighty-nine".