1311561321564 has 48 divisors (see below), whose sum is σ = 3295917378432. Its totient is φ = 403532939712.

The previous prime is 1311561321563. The next prime is 1311561321583. The reversal of 1311561321564 is 4651231651131.

It is a super-2 number, since 2×1311561321564² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311561321563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2425687 + ... + 2916689.

It is an arithmetic number, because the mean of its divisors is an integer number (68664945384).

Almost surely, 2^{1311561321564} is an apocalyptic number.

It is an amenable number.

1311561321564 is an abundant number, since it is smaller than the sum of its proper divisors (1984356056868).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1311561321564 is a wasteful number, since it uses less digits than its factorization.

1311561321564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 508146 (or 508144 counting only the distinct ones).

The product of its digits is 64800, while the sum is 39.

Adding to 1311561321564 its reverse (4651231651131), we get a palindrome (5962792972695).

The spelling of 1311561321564 in words is "one trillion, three hundred eleven billion, five hundred sixty-one million, three hundred twenty-one thousand, five hundred sixty-four".