261539355896 has 96 divisors (see below), whose sum is σ = 623651505120. Its totient is φ = 100128234240.

The previous prime is 261539355893. The next prime is 261539355941. The reversal of 261539355896 is 698553935162.

It is a Harshad number since it is a multiple of its sum of digits (62).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261539355893) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 512690 + ... + 886526.

It is an arithmetic number, because the mean of its divisors is an integer number (6496369845).

Almost surely, 2^261539355896 is an apocalyptic number.

261539355896 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261539355896, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (311825752560).

261539355896 is an abundant number, since it is smaller than the sum of its proper divisors (362112149224).

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

261539355896 is a wasteful number, since it uses less digits than its factorization.

261539355896 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373925 (or 373890 counting only the distinct ones).

The product of its digits is 52488000, while the sum is 62.

The spelling of 261539355896 in words is "two hundred sixty-one billion, five hundred thirty-nine million, three hundred fifty-five thousand, eight hundred ninety-six".