1340212021 has 4 divisors (see below), whose sum is σ = 1340309932. Its totient is φ = 1340114112.

The previous prime is 1340212019. The next prime is 1340212031. The reversal of 1340212021 is 1202120431.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1202120431 = 6569 ⋅182999.

It can be written as a sum of positive squares in 2 ways, for example, as 758727025 + 581484996 = 27545^2 + 24114^2 .

It is a cyclic number.

It is not a de Polignac number, because 1340212021 - 2¹ = 1340212019 is a prime.

It is a super-2 number, since 2×1340212021² = 3592336522465808882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1340211986 and 1340212004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1340212031) 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, 24276 + ... + 57181.

It is an arithmetic number, because the mean of its divisors is an integer number (335077483).

Almost surely, 2^1340212021 is an apocalyptic number.

It is an amenable number.

1340212021 is a deficient number, since it is larger than the sum of its proper divisors (97911).

1340212021 is an equidigital number, since it uses as much as digits as its factorization.

1340212021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97910.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 1340212021 is about 36608.9063070723. The cubic root of 1340212021 is about 1102.5319145503.

Adding to 1340212021 its reverse (1202120431), we get a palindrome (2542332452).

The spelling of 1340212021 in words is "one billion, three hundred forty million, two hundred twelve thousand, twenty-one".