1383655811521 has 27 divisors (see below), whose sum is σ = 1459413953571. Its totient is φ = 1311722210304.

The previous prime is 1383655811509. The next prime is 1383655811533. The reversal of 1383655811521 is 1251185563831.

The square root of 1383655811521 is 1176289.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (1383655811509) and next prime (1383655811533).

It can be written as a sum of positive squares in only one way, i.e., 1362204108225 + 21451703296 = 1167135^2 + 146464^2 .

It is not a de Polignac number, because 1383655811521 - 2⁷ = 1383655811393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1383655811221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 5383874625 + ... + 5383874881.

Almost surely, 2^{1383655811521} is an apocalyptic number.

1383655811521 is the 1176289-th square number.

1383655811521 is the 588145-th centered octagonal number.

It is an amenable number.

1383655811521 is a deficient number, since it is larger than the sum of its proper divisors (75758142050).

1383655811521 is an frugal number, since it uses more digits than its factorization.

1383655811521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 958 (or 479 counting only the distinct ones).

The product of its digits is 864000, while the sum is 49.

Multiplying 1383655811521 by its sum of digits (49), we get a square (67799134764529 = 8234023²).

The spelling of 1383655811521 in words is "one trillion, three hundred eighty-three billion, six hundred fifty-five million, eight hundred eleven thousand, five hundred twenty-one".