2138603820521 has 12 divisors (see below), whose sum is σ = 2487805064388. Its totient is φ = 1833058456992.

The previous prime is 2138603820503. The next prime is 2138603820539. The reversal of 2138603820521 is 1250283068312.

It is an interprime number because it is at equal distance from previous prime (2138603820503) and next prime (2138603820539).

It can be written as a sum of positive squares in 2 ways, for example, as 1625574000400 + 513029820121 = 1274980^2 + 716261^2 .

It is a de Polignac number, because none of the positive numbers 2^k-2138603820521 is a prime.

It is a super-2 number, since 2×2138603820521² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2138603820421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2905355 + ... + 3566271.

It is an arithmetic number, because the mean of its divisors is an integer number (207317088699).

Almost surely, 2^{2138603820521} is an apocalyptic number.

It is an amenable number.

2138603820521 is a deficient number, since it is larger than the sum of its proper divisors (349201243867).

2138603820521 is an equidigital number, since it uses as much as digits as its factorization.

2138603820521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 726968 (or 726961 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 41.

Adding to 2138603820521 its reverse (1250283068312), we get a palindrome (3388886888833).

The spelling of 2138603820521 in words is "two trillion, one hundred thirty-eight billion, six hundred three million, eight hundred twenty thousand, five hundred twenty-one".