311520661 has 4 divisors (see below), whose sum is σ = 311556672. Its totient is φ = 311484652.

The previous prime is 311520647. The next prime is 311520667. The reversal of 311520661 is 166025113.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 311520661 - 2¹³ = 311512469 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 (311520667) 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, 3666 + ... + 25228.

It is an arithmetic number, because the mean of its divisors is an integer number (77889168).

Almost surely, 2^311520661 is an apocalyptic number.

It is an amenable number.

311520661 is a deficient number, since it is larger than the sum of its proper divisors (36011).

311520661 is a wasteful number, since it uses less digits than its factorization.

311520661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36010.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 311520661 is about 17649.9479036058. The cubic root of 311520661 is about 677.8947729884.

Adding to 311520661 its reverse (166025113), we get a palindrome (477545774).

The spelling of 311520661 in words is "three hundred eleven million, five hundred twenty thousand, six hundred sixty-one".