261450408891 has 16 divisors (see below), whose sum is σ = 398654270208. Its totient is φ = 149305116000.

The previous prime is 261450408887. The next prime is 261450408893. The reversal of 261450408891 is 198804054162.

It is not a de Polignac number, because 261450408891 - 2² = 261450408887 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261450408891.

It is not an unprimeable number, because it can be changed into a prime (261450408893) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3929460 + ... + 3995441.

It is an arithmetic number, because the mean of its divisors is an integer number (24915891888).

Almost surely, 2^261450408891 is an apocalyptic number.

261450408891 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

261450408891 is a deficient number, since it is larger than the sum of its proper divisors (137203861317).

261450408891 is a wasteful number, since it uses less digits than its factorization.

261450408891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7926482.

The product of its (nonzero) digits is 552960, while the sum is 48.

The spelling of 261450408891 in words is "two hundred sixty-one billion, four hundred fifty million, four hundred eight thousand, eight hundred ninety-one".