21366516331 has 4 divisors (see below), whose sum is σ = 21405578152. Its totient is φ = 21327454512.

The previous prime is 21366516323. The next prime is 21366516337. The reversal of 21366516331 is 13361566312.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21366516331 - 2³ = 21366516323 is a prime.

It is a super-2 number, since 2×21366516331² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21366516337) 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, 19530090 + ... + 19531183.

It is an arithmetic number, because the mean of its divisors is an integer number (5351394538).

Almost surely, 2^21366516331 is an apocalyptic number.

21366516331 is a deficient number, since it is larger than the sum of its proper divisors (39061821).

21366516331 is an equidigital number, since it uses as much as digits as its factorization.

21366516331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39061820.

The product of its digits is 58320, while the sum is 37.

The spelling of 21366516331 in words is "twenty-one billion, three hundred sixty-six million, five hundred sixteen thousand, three hundred thirty-one".