1988732138521 has 2 divisors, whose sum is σ = 1988732138522. Its totient is φ = 1988732138520.

The previous prime is 1988732138501. The next prime is 1988732138593. The reversal of 1988732138521 is 1258312378891.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1657720625625 + 331011512896 = 1287525^2 + 575336^2 .

It is a cyclic number.

It is not a de Polignac number, because 1988732138521 - 2⁹ = 1988732138009 is a prime.

It is not a weakly prime, because it can be changed into another prime (1988732138501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994366069260 + 994366069261.

It is an arithmetic number, because the mean of its divisors is an integer number (994366069261).

Almost surely, 2^{1988732138521} is an apocalyptic number.

It is an amenable number.

1988732138521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1988732138521 is an equidigital number, since it uses as much as digits as its factorization.

1988732138521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5806080, while the sum is 58.

The spelling of 1988732138521 in words is "one trillion, nine hundred eighty-eight billion, seven hundred thirty-two million, one hundred thirty-eight thousand, five hundred twenty-one".