261191493394 has 8 divisors (see below), whose sum is σ = 421924720140. Its totient is φ = 120549920016.

The previous prime is 261191493391. The next prime is 261191493469. The reversal of 261191493394 is 493394191162.

261191493394 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 258862176225 + 2329317169 = 508785^2 + 48263^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (261191493391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5022913309 + ... + 5022913360.

Almost surely, 2^261191493394 is an apocalyptic number.

261191493394 is a deficient number, since it is larger than the sum of its proper divisors (160733226746).

261191493394 is a wasteful number, since it uses less digits than its factorization.

261191493394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10045826684.

The product of its digits is 1259712, while the sum is 52.

The spelling of 261191493394 in words is "two hundred sixty-one billion, one hundred ninety-one million, four hundred ninety-three thousand, three hundred ninety-four".