1321021013 has 4 divisors (see below), whose sum is σ = 1422638028. Its totient is φ = 1219404000.

The previous prime is 1321021007. The next prime is 1321021069. The reversal of 1321021013 is 3101201231.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3101201231 = 379 ⋅8182589.

It can be written as a sum of positive squares in 2 ways, for example, as 558046129 + 762974884 = 23623^2 + 27622^2 .

It is a cyclic number.

It is not a de Polignac number, because 1321021013 - 2²⁸ = 1052585557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321021913) 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, 50808488 + ... + 50808513.

It is an arithmetic number, because the mean of its divisors is an integer number (355659507).

Almost surely, 2^1321021013 is an apocalyptic number.

1321021013 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1321021013 is a deficient number, since it is larger than the sum of its proper divisors (101617015).

1321021013 is a wasteful number, since it uses less digits than its factorization.

1321021013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101617014.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 1321021013 is about 36345.8527620415. The cubic root of 1321021013 is about 1097.2440688472.

Adding to 1321021013 its reverse (3101201231), we get a palindrome (4422222244).

The spelling of 1321021013 in words is "one billion, three hundred twenty-one million, twenty-one thousand, thirteen".