261639440475 has 24 divisors (see below), whose sum is σ = 494373953280. Its totient is φ = 119606601120.

The previous prime is 261639440467. The next prime is 261639440477. The reversal of 261639440475 is 574044936162.

It is not a de Polignac number, because 261639440475 - 2³ = 261639440467 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261639440477) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 249179895 + ... + 249180944.

It is an arithmetic number, because the mean of its divisors is an integer number (20598914720).

Almost surely, 2^261639440475 is an apocalyptic number.

261639440475 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

261639440475 is a deficient number, since it is larger than the sum of its proper divisors (232734512805).

261639440475 is a wasteful number, since it uses less digits than its factorization.

261639440475 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 498360859 (or 498360854 counting only the distinct ones).

The product of its (nonzero) digits is 4354560, while the sum is 51.

The spelling of 261639440475 in words is "two hundred sixty-one billion, six hundred thirty-nine million, four hundred forty thousand, four hundred seventy-five".