261222757 has 4 divisors (see below), whose sum is σ = 266780736. Its totient is φ = 255664780.

The previous prime is 261222739. The next prime is 261222761. The reversal of 261222757 is 757222162.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 261222757 - 2¹⁹ = 260698469 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 (261223757) 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, 2778919 + ... + 2779012.

It is an arithmetic number, because the mean of its divisors is an integer number (66695184).

Almost surely, 2^261222757 is an apocalyptic number.

It is an amenable number.

261222757 is a deficient number, since it is larger than the sum of its proper divisors (5557979).

261222757 is an equidigital number, since it uses as much as digits as its factorization.

261222757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5557978.

The product of its digits is 23520, while the sum is 34.

The square root of 261222757 is about 16162.3871071077. The cubic root of 261222757 is about 639.2494105832.

The spelling of 261222757 in words is "two hundred sixty-one million, two hundred twenty-two thousand, seven hundred fifty-seven".