11387531021 has 2 divisors, whose sum is σ = 11387531022. Its totient is φ = 11387531020.

The previous prime is 11387531009. The next prime is 11387531047. The reversal of 11387531021 is 12013578311.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9537670921 + 1849860100 = 97661^2 + 43010^2 .

It is a cyclic number.

It is not a de Polignac number, because 11387531021 - 2¹⁴ = 11387514637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11387531621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5693765510 + 5693765511.

It is an arithmetic number, because the mean of its divisors is an integer number (5693765511).

Almost surely, 2^11387531021 is an apocalyptic number.

It is an amenable number.

11387531021 is a deficient number, since it is larger than the sum of its proper divisors (1).

11387531021 is an equidigital number, since it uses as much as digits as its factorization.

11387531021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5040, while the sum is 32.

The spelling of 11387531021 in words is "eleven billion, three hundred eighty-seven million, five hundred thirty-one thousand, twenty-one".