261516435810 has 128 divisors (see below), whose sum is σ = 725306448384. Its totient is φ = 59109212160.

The previous prime is 261516435787. The next prime is 261516435821. The reversal of 261516435810 is 18534615162.

It is a super-2 number, since 2×261516435810² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 27718854 + ... + 27728286.

It is an arithmetic number, because the mean of its divisors is an integer number (5666456628).

Almost surely, 2^261516435810 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261516435810, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (362653224192).

261516435810 is an abundant number, since it is smaller than the sum of its proper divisors (463790012574).

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

261516435810 is a wasteful number, since it uses less digits than its factorization.

261516435810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10908.

The product of its (nonzero) digits is 172800, while the sum is 42.

The spelling of 261516435810 in words is "two hundred sixty-one billion, five hundred sixteen million, four hundred thirty-five thousand, eight hundred ten".