1311355520021 has 4 divisors (see below), whose sum is σ = 1317236038272. Its totient is φ = 1305475001772.

The previous prime is 1311355519961. The next prime is 1311355520023. The reversal of 1311355520021 is 1200255531131.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1311355520021 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311355520023) 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, 2940258791 + ... + 2940259236.

It is an arithmetic number, because the mean of its divisors is an integer number (329309009568).

Almost surely, 2^{1311355520021} is an apocalyptic number.

It is an amenable number.

1311355520021 is a deficient number, since it is larger than the sum of its proper divisors (5880518251).

1311355520021 is an equidigital number, since it uses as much as digits as its factorization.

1311355520021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5880518250.

The product of its (nonzero) digits is 4500, while the sum is 29.

The spelling of 1311355520021 in words is "one trillion, three hundred eleven billion, three hundred fifty-five million, five hundred twenty thousand, twenty-one".