261450408981 has 4 divisors (see below), whose sum is σ = 348600545312. Its totient is φ = 174300272652.

The previous prime is 261450408931. The next prime is 261450408983. The reversal of 261450408981 is 189804054162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 261450408981 - 2⁷ = 261450408853 is a prime.

It is a super-2 number, since 2×261450408981² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261450408981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261450408983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43575068161 + ... + 43575068166.

It is an arithmetic number, because the mean of its divisors is an integer number (87150136328).

Almost surely, 2^261450408981 is an apocalyptic number.

It is an amenable number.

261450408981 is a deficient number, since it is larger than the sum of its proper divisors (87150136331).

261450408981 is an equidigital number, since it uses as much as digits as its factorization.

261450408981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87150136330.

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

The spelling of 261450408981 in words is "two hundred sixty-one billion, four hundred fifty million, four hundred eight thousand, nine hundred eighty-one".