1331100021 has 4 divisors (see below), whose sum is σ = 1774800032. Its totient is φ = 887400012.

The previous prime is 1331100013. The next prime is 1331100037. The reversal of 1331100021 is 1200011331.

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: 1200011331 = 3 ⋅400003777.

It is not a de Polignac number, because 1331100021 - 2³ = 1331100013 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 (1331100011) 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, 221850001 + ... + 221850006.

It is an arithmetic number, because the mean of its divisors is an integer number (443700008).

Almost surely, 2^1331100021 is an apocalyptic number.

It is an amenable number.

1331100021 is a deficient number, since it is larger than the sum of its proper divisors (443700011).

1331100021 is an equidigital number, since it uses as much as digits as its factorization.

1331100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 443700010.

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 1331100021 is about 36484.2434620755. The cubic root of 1331100021 is about 1100.0275533043.

Adding to 1331100021 its reverse (1200011331), we get a palindrome (2531111352).

The spelling of 1331100021 in words is "one billion, three hundred thirty-one million, one hundred thousand, twenty-one".