1331213021 has 4 divisors (see below), whose sum is σ = 1389091872. Its totient is φ = 1273334172.

The previous prime is 1331213011. The next prime is 1331213063. The reversal of 1331213021 is 1203121331.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1203121331 = 17 ⋅70771843.

It is a cyclic number.

It is not a de Polignac number, because 1331213021 - 2¹⁰ = 1331211997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1331213011) 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, 28939391 + ... + 28939436.

It is an arithmetic number, because the mean of its divisors is an integer number (347272968).

Almost surely, 2^1331213021 is an apocalyptic number.

It is an amenable number.

1331213021 is a deficient number, since it is larger than the sum of its proper divisors (57878851).

1331213021 is an equidigital number, since it uses as much as digits as its factorization.

1331213021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57878850.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 1331213021 is about 36485.7920429309. The cubic root of 1331213021 is about 1100.0586803407.

Adding to 1331213021 its reverse (1203121331), we get a palindrome (2534334352).

The spelling of 1331213021 in words is "one billion, three hundred thirty-one million, two hundred thirteen thousand, twenty-one".