1311020003921 has 2 divisors, whose sum is σ = 1311020003922. Its totient is φ = 1311020003920.

The previous prime is 1311020003861. The next prime is 1311020003927. The reversal of 1311020003921 is 1293000201131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1180004238400 + 131015765521 = 1086280^2 + 361961^2 .

It is an emirp because it is prime and its reverse (1293000201131) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1311020003921 is a prime.

It is not a weakly prime, because it can be changed into another prime (1311020003927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 655510001960 + 655510001961.

It is an arithmetic number, because the mean of its divisors is an integer number (655510001961).

Almost surely, 2^{1311020003921} is an apocalyptic number.

It is an amenable number.

1311020003921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1311020003921 is an equidigital number, since it uses as much as digits as its factorization.

1311020003921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 23.

The spelling of 1311020003921 in words is "one trillion, three hundred eleven billion, twenty million, three thousand, nine hundred twenty-one".