21331312306 has 4 divisors (see below), whose sum is σ = 31996968462. Its totient is φ = 10665656152.

The previous prime is 21331312279. The next prime is 21331312339. The reversal of 21331312306 is 60321313312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 18029775625 + 3301536681 = 134275^2 + 57459^2 .

It is a super-2 number, since 2×21331312306² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5332828075 + ... + 5332828078.

Almost surely, 2^21331312306 is an apocalyptic number.

21331312306 is a deficient number, since it is larger than the sum of its proper divisors (10665656156).

21331312306 is a wasteful number, since it uses less digits than its factorization.

21331312306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10665656155.

The product of its (nonzero) digits is 1944, while the sum is 25.

Adding to 21331312306 its reverse (60321313312), we get a palindrome (81652625618).

The spelling of 21331312306 in words is "twenty-one billion, three hundred thirty-one million, three hundred twelve thousand, three hundred six".