31211212421 has 4 divisors (see below), whose sum is σ = 31417909344. Its totient is φ = 31004515500.

The previous prime is 31211212381. The next prime is 31211212423. The reversal of 31211212421 is 12421211213.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12421211213 = 229 ⋅54241097.

It is a cyclic number.

It is not a de Polignac number, because 31211212421 - 2³⁴ = 14031343237 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31211212393 and 31211212402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31211212423) 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, 103348235 + ... + 103348536.

It is an arithmetic number, because the mean of its divisors is an integer number (7854477336).

Almost surely, 2^31211212421 is an apocalyptic number.

It is an amenable number.

31211212421 is a deficient number, since it is larger than the sum of its proper divisors (206696923).

31211212421 is a wasteful number, since it uses less digits than its factorization.

31211212421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206696922.

The product of its digits is 192, while the sum is 20.

Adding to 31211212421 its reverse (12421211213), we get a palindrome (43632423634).

The spelling of 31211212421 in words is "thirty-one billion, two hundred eleven million, two hundred twelve thousand, four hundred twenty-one".