261587239936 has 99 divisors (see below), whose sum is σ = 575174614413. Its totient is φ = 118821457920.

The previous prime is 261587239861. The next prime is 261587239939. The reversal of 261587239936 is 639932785162.

The square root of 261587239936 is 511456.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 255146214400 + 6441025536 = 505120^2 + 80256^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261587239939) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 180031786 + ... + 180033238.

Almost surely, 2^261587239936 is an apocalyptic number.

261587239936 is the 511456-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261587239936

261587239936 is an abundant number, since it is smaller than the sum of its proper divisors (313587374477).

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

261587239936 is an frugal number, since it uses more digits than its factorization.

261587239936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2948 (or 1466 counting only the distinct ones).

The product of its digits is 29393280, while the sum is 61.

The spelling of 261587239936 in words is "two hundred sixty-one billion, five hundred eighty-seven million, two hundred thirty-nine thousand, nine hundred thirty-six".