1311020999 has 4 divisors (see below), whose sum is σ = 1368021936. Its totient is φ = 1254020064.

The previous prime is 1311020987. The next prime is 1311021001. The reversal of 1311020999 is 9990201131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9990201131 = 10271 ⋅972661.

It is a cyclic number.

It is not a de Polignac number, because 1311020999 - 2⁴ = 1311020983 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 (1311020929) 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, 28500434 + ... + 28500479.

It is an arithmetic number, because the mean of its divisors is an integer number (342005484).

Almost surely, 2^1311020999 is an apocalyptic number.

1311020999 is a deficient number, since it is larger than the sum of its proper divisors (57000937).

1311020999 is an equidigital number, since it uses as much as digits as its factorization.

1311020999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57000936.

The product of its (nonzero) digits is 4374, while the sum is 35.

The square root of 1311020999 is about 36208.0239587857. The cubic root of 1311020999 is about 1094.4683724186.

The spelling of 1311020999 in words is "one billion, three hundred eleven million, twenty thousand, nine hundred ninety-nine".