1321513521551 has 64 divisors (see below), whose sum is σ = 1471837796352. Its totient is φ = 1181368320000.

The previous prime is 1321513521451. The next prime is 1321513521623. The reversal of 1321513521551 is 1551253151231.

It is a cyclic number.

It is not a de Polignac number, because 1321513521551 - 2¹⁰ = 1321513520527 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 (1321513521451) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2866623461 + ... + 2866623921.

It is an arithmetic number, because the mean of its divisors is an integer number (22997465568).

Almost surely, 2^{1321513521551} is an apocalyptic number.

1321513521551 is a deficient number, since it is larger than the sum of its proper divisors (150324274801).

1321513521551 is a wasteful number, since it uses less digits than its factorization.

1321513521551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1124.

The product of its digits is 22500, while the sum is 35.

Adding to 1321513521551 its reverse (1551253151231), we get a palindrome (2872766672782).

The spelling of 1321513521551 in words is "one trillion, three hundred twenty-one billion, five hundred thirteen million, five hundred twenty-one thousand, five hundred fifty-one".