261445779445 has 16 divisors (see below), whose sum is σ = 324820283760. Its totient is φ = 201778253824.

The previous prime is 261445779443. The next prime is 261445779461. The reversal of 261445779445 is 544977544162.

It can be written as a sum of positive squares in 8 ways, for example, as 13833052996 + 247612726449 = 117614^2 + 497607^2 .

It is a cyclic number.

It is not a de Polignac number, because 261445779445 - 2¹ = 261445779443 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261445779445.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261445779443) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 564322 + ... + 917251.

It is an arithmetic number, because the mean of its divisors is an integer number (20301267735).

Almost surely, 2^261445779445 is an apocalyptic number.

It is an amenable number.

261445779445 is a deficient number, since it is larger than the sum of its proper divisors (63374504315).

261445779445 is a wasteful number, since it uses less digits than its factorization.

261445779445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1482824.

The product of its digits is 33868800, while the sum is 58.

The spelling of 261445779445 in words is "two hundred sixty-one billion, four hundred forty-five million, seven hundred seventy-nine thousand, four hundred forty-five".