1321211021 has 4 divisors (see below), whose sum is σ = 1422842652. Its totient is φ = 1219579392.

The previous prime is 1321211009. The next prime is 1321211027. The reversal of 1321211021 is 1201121231.

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 71588521 + 1249622500 = 8461^2 + 35350^2 .

It is a cyclic number.

It is not a de Polignac number, because 1321211021 - 2²² = 1317016717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1321210987 and 1321211005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321211027) 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, 50815796 + ... + 50815821.

It is an arithmetic number, because the mean of its divisors is an integer number (355710663).

Almost surely, 2^1321211021 is an apocalyptic number.

It is an amenable number.

1321211021 is a deficient number, since it is larger than the sum of its proper divisors (101631631).

1321211021 is a wasteful number, since it uses less digits than its factorization.

1321211021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101631630.

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

The square root of 1321211021 is about 36348.4665563762. The cubic root of 1321211021 is about 1097.2966733993.

Adding to 1321211021 its reverse (1201121231), we get a palindrome (2522332252).

The spelling of 1321211021 in words is "one billion, three hundred twenty-one million, two hundred eleven thousand, twenty-one".