261762551 has 4 divisors (see below), whose sum is σ = 264461232. Its totient is φ = 259063872.

The previous prime is 261762541. The next prime is 261762559. The reversal of 261762551 is 155267162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 155267162 = 2 ⋅77633581.

It is a cyclic number.

It is not a de Polignac number, because 261762551 - 2¹⁴ = 261746167 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261762559) 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, 1349195 + ... + 1349388.

It is an arithmetic number, because the mean of its divisors is an integer number (66115308).

Almost surely, 2^261762551 is an apocalyptic number.

261762551 is a deficient number, since it is larger than the sum of its proper divisors (2698681).

261762551 is an equidigital number, since it uses as much as digits as its factorization.

261762551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2698680.

The product of its digits is 25200, while the sum is 35.

The square root of 261762551 is about 16179.0775695032. The cubic root of 261762551 is about 639.6894253200.

The spelling of 261762551 in words is "two hundred sixty-one million, seven hundred sixty-two thousand, five hundred fifty-one".