261891398 has 8 divisors (see below), whose sum is σ = 393014160. Its totient is φ = 130886680.

The previous prime is 261891397. The next prime is 261891403. The reversal of 261891398 is 893198162.

261891398 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261891397) 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, 23738 + ... + 32973.

It is an arithmetic number, because the mean of its divisors is an integer number (49126770).

Almost surely, 2^261891398 is an apocalyptic number.

261891398 is a deficient number, since it is larger than the sum of its proper divisors (131122762).

261891398 is a wasteful number, since it uses less digits than its factorization.

261891398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59022.

The product of its digits is 186624, while the sum is 47.

The square root of 261891398 is about 16183.0589815399. The cubic root of 261891398 is about 639.7943659023.

The spelling of 261891398 in words is "two hundred sixty-one million, eight hundred ninety-one thousand, three hundred ninety-eight".