611311261 has 4 divisors (see below), whose sum is σ = 666885024. Its totient is φ = 555737500.

The previous prime is 611311249. The next prime is 611311277. The reversal of 611311261 is 162113116.

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 611311261 - 2⁵ = 611311229 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 (611311361) 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, 27786865 + ... + 27786886.

It is an arithmetic number, because the mean of its divisors is an integer number (166721256).

Almost surely, 2^611311261 is an apocalyptic number.

It is an amenable number.

611311261 is a deficient number, since it is larger than the sum of its proper divisors (55573763).

611311261 is a wasteful number, since it uses less digits than its factorization.

611311261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55573762.

The product of its digits is 216, while the sum is 22.

The square root of 611311261 is about 24724.7095230662. The cubic root of 611311261 is about 848.6998628782.

Adding to 611311261 its reverse (162113116), we get a palindrome (773424377).

The spelling of 611311261 in words is "six hundred eleven million, three hundred eleven thousand, two hundred sixty-one".