661623311 has 8 divisors (see below), whose sum is σ = 664486320.
Its totient is φ = 658766592.
The previous prime is 661623283. The next prime is 661623329. The reversal of 661623311 is 113326166.
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 661623311 - 26 = 661623247 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 (661625311) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (17) of ones.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 395585 + ... + 397253.
It is an arithmetic number, because the mean of its divisors is an integer number (83060790).
Almost surely, 2661623311 is an apocalyptic number.
661623311 is a deficient number, since it is larger than the sum of its proper divisors (2863009).
661623311 is a wasteful number, since it uses less digits than its factorization.
661623311 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 3145.
The product of its digits is 3888, while the sum is 29.
The square root of 661623311 is about 25722.0394020381.
The cubic root of 661623311 is about 871.3719978028.
Adding to 661623311 its reverse (113326166), we get a palindrome (774949477).
The spelling of 661623311 in words is "six hundred sixty-one million, six hundred twenty-three thousand, three hundred eleven".