261375599551 has 8 divisors (see below), whose sum is σ = 285141622608. Its totient is φ = 237610344000.

The previous prime is 261375599531. The next prime is 261375599581. The reversal of 261375599551 is 155995573162.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 261375599551 - 2²⁵ = 261342045119 is a prime.

It is a super-2 number, since 2×261375599551² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261375599531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 700771 + ... + 1006891.

It is an arithmetic number, because the mean of its divisors is an integer number (35642702826).

Almost surely, 2^261375599551 is an apocalyptic number.

261375599551 is a deficient number, since it is larger than the sum of its proper divisors (23766023057).

261375599551 is a wasteful number, since it uses less digits than its factorization.

261375599551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 383753.

The product of its digits is 12757500, while the sum is 58.

The spelling of 261375599551 in words is "two hundred sixty-one billion, three hundred seventy-five million, five hundred ninety-nine thousand, five hundred fifty-one".