31333320021 has 4 divisors (see below), whose sum is σ = 41777760032. Its totient is φ = 20888880012.

The previous prime is 31333319993. The next prime is 31333320113. The reversal of 31333320021 is 12002333313.

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 not a de Polignac number, because 31333320021 - 2⁵ = 31333319989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31333320021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31333322021) 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, 5222220001 + ... + 5222220006.

It is an arithmetic number, because the mean of its divisors is an integer number (10444440008).

Almost surely, 2^31333320021 is an apocalyptic number.

It is an amenable number.

31333320021 is a deficient number, since it is larger than the sum of its proper divisors (10444440011).

31333320021 is a wasteful number, since it uses less digits than its factorization.

31333320021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10444440010.

The product of its (nonzero) digits is 972, while the sum is 21.

Adding to 31333320021 its reverse (12002333313), we get a palindrome (43335653334).

The spelling of 31333320021 in words is "thirty-one billion, three hundred thirty-three million, three hundred twenty thousand, twenty-one".