31212213421 has 2 divisors, whose sum is σ = 31212213422. Its totient is φ = 31212213420.

The previous prime is 31212213343. The next prime is 31212213427. The reversal of 31212213421 is 12431221213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17832664521 + 13379548900 = 133539^2 + 115670^2 .

It is a cyclic number.

It is not a de Polignac number, because 31212213421 - 2¹⁹ = 31211689133 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31212213392 and 31212213401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31212213427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15606106710 + 15606106711.

It is an arithmetic number, because the mean of its divisors is an integer number (15606106711).

Almost surely, 2^31212213421 is an apocalyptic number.

It is an amenable number.

31212213421 is a deficient number, since it is larger than the sum of its proper divisors (1).

31212213421 is an equidigital number, since it uses as much as digits as its factorization.

31212213421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 22.

Adding to 31212213421 its reverse (12431221213), we get a palindrome (43643434634).

The spelling of 31212213421 in words is "thirty-one billion, two hundred twelve million, two hundred thirteen thousand, four hundred twenty-one".