31212220021 has 8 divisors (see below), whose sum is σ = 32339692800. Its totient is φ = 30088159920.

The previous prime is 31212220009. The next prime is 31212220103. The reversal of 31212220021 is 12002221213.

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 a de Polignac number, because none of the positive numbers 2^k-31212220021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31212219977 and 31212220004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31212220321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 834541 + ... + 871138.

It is an arithmetic number, because the mean of its divisors is an integer number (4042461600).

Almost surely, 2^31212220021 is an apocalyptic number.

It is an amenable number.

31212220021 is a deficient number, since it is larger than the sum of its proper divisors (1127472779).

31212220021 is a wasteful number, since it uses less digits than its factorization.

31212220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1706339.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 31212220021 its reverse (12002221213), we get a palindrome (43214441234).

The spelling of 31212220021 in words is "thirty-one billion, two hundred twelve million, two hundred twenty thousand, twenty-one".