261735631560 has 256 divisors, whose sum is σ = 949254969600. Its totient is φ = 63762702336.

The previous prime is 261735631537. The next prime is 261735631561. The reversal of 261735631560 is 65136537162.

261735631560 is a `hidden beast` number, since 2 + 6 + 1 + 7 + 3 + 5 + 631 + 5 + 6 + 0 = 666.

It is a super-2 number, since 2×261735631560² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (261735631561) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1265787 + ... + 1457973.

It is an arithmetic number, because the mean of its divisors is an integer number (3708027225).

Almost surely, 2^261735631560 is an apocalyptic number.

261735631560 is a gapful number since it is divisible by the number (20) 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 261735631560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (474627484800).

261735631560 is an abundant number, since it is smaller than the sum of its proper divisors (687519338040).

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

261735631560 is a wasteful number, since it uses less digits than its factorization.

261735631560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192317 (or 192307 counting only the distinct ones).

The product of its (nonzero) digits is 680400, while the sum is 45.

The spelling of 261735631560 in words is "two hundred sixty-one billion, seven hundred thirty-five million, six hundred thirty-one thousand, five hundred sixty".