31210020221 has 4 divisors (see below), whose sum is σ = 31256121372. Its totient is φ = 31163919072.

The previous prime is 31210020203. The next prime is 31210020241. The reversal of 31210020221 is 12202001213.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12202001213 = 383 ⋅31859011.

It can be written as a sum of positive squares in 2 ways, for example, as 28177315321 + 3032704900 = 167861^2 + 55070^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31210020221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31210020196 and 31210020205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31210020241) 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, 23049560 + ... + 23050913.

It is an arithmetic number, because the mean of its divisors is an integer number (7814030343).

Almost surely, 2^31210020221 is an apocalyptic number.

It is an amenable number.

31210020221 is a deficient number, since it is larger than the sum of its proper divisors (46101151).

31210020221 is an equidigital number, since it uses as much as digits as its factorization.

31210020221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46101150.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 31210020221 its reverse (12202001213), we get a palindrome (43412021434).

The spelling of 31210020221 in words is "thirty-one billion, two hundred ten million, twenty thousand, two hundred twenty-one".