1312210021 has 4 divisors (see below), whose sum is σ = 1312338412. Its totient is φ = 1312081632.

The previous prime is 1312209971. The next prime is 1312210027. The reversal of 1312210021 is 1200122131.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 166048996 + 1146161025 = 12886^2 + 33855^2 .

It is a cyclic number.

It is not a de Polignac number, because 1312210021 - 2¹³ = 1312201829 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1312209983 and 1312210010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1312210027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47400 + ... + 69793.

It is an arithmetic number, because the mean of its divisors is an integer number (328084603).

Almost surely, 2^1312210021 is an apocalyptic number.

It is an amenable number.

1312210021 is a deficient number, since it is larger than the sum of its proper divisors (128391).

1312210021 is a wasteful number, since it uses less digits than its factorization.

1312210021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128390.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1312210021 is about 36224.4395539807. The cubic root of 1312210021 is about 1094.7991461072.

Adding to 1312210021 its reverse (1200122131), we get a palindrome (2512332152).

The spelling of 1312210021 in words is "one billion, three hundred twelve million, two hundred ten thousand, twenty-one".