261406405120 has 160 divisors (see below), whose sum is σ = 758436421248. Its totient is φ = 84352892928.

The previous prime is 261406405109. The next prime is 261406405153. The reversal of 261406405120 is 21504604162.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (160).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 124402 + ... + 733681.

Almost surely, 2^261406405120 is an apocalyptic number.

261406405120 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 261406405120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (379218210624).

261406405120 is an abundant number, since it is smaller than the sum of its proper divisors (497030016128).

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

261406405120 is an equidigital number, since it uses as much as digits as its factorization.

261406405120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 858130 (or 858114 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 31.

The spelling of 261406405120 in words is "two hundred sixty-one billion, four hundred six million, four hundred five thousand, one hundred twenty".