261040010100 has 144 divisors (see below), whose sum is σ = 795263474880. Its totient is φ = 65927347200.

The previous prime is 261040010071. The next prime is 261040010107. The reversal of 261040010100 is 1010040162.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 261040010100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261040010107) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 34612330 + ... + 34619870.

It is an arithmetic number, because the mean of its divisors is an integer number (5522663020).

Almost surely, 2^261040010100 is an apocalyptic number.

261040010100 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 261040010100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (397631737440).

261040010100 is an abundant number, since it is smaller than the sum of its proper divisors (534223464780).

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

261040010100 is a wasteful number, since it uses less digits than its factorization.

261040010100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13650 (or 13643 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 261040010100 its reverse (1010040162), we get a palindrome (262050050262).

The spelling of 261040010100 in words is "two hundred sixty-one billion, forty million, ten thousand, one hundred".