1311212021 has 24 divisors (see below), whose sum is σ = 1644773760. Its totient is φ = 1038744000.

The previous prime is 1311212017. The next prime is 1311212041. The reversal of 1311212021 is 1202121131.

It is not a de Polignac number, because 1311212021 - 2² = 1311212017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1311211987 and 1311212005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311212041) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20996 + ... + 55346.

It is an arithmetic number, because the mean of its divisors is an integer number (68532240).

Almost surely, 2^1311212021 is an apocalyptic number.

It is an amenable number.

1311212021 is a deficient number, since it is larger than the sum of its proper divisors (333561739).

1311212021 is a wasteful number, since it uses less digits than its factorization.

1311212021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34425 (or 34418 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 14.

The square root of 1311212021 is about 36210.6617034265. The cubic root of 1311212021 is about 1094.5215262543.

Adding to 1311212021 its reverse (1202121131), we get a palindrome (2513333152).

The spelling of 1311212021 in words is "one billion, three hundred eleven million, two hundred twelve thousand, twenty-one".