21152165513021 has 8 divisors (see below), whose sum is σ = 21216926907000. Its totient is φ = 21087482572800.

The previous prime is 21152165512997. The next prime is 21152165513023. The reversal of 21152165513021 is 12031556125112.

It can be written as a sum of positive squares in 4 ways, for example, as 525907788025 + 20626257724996 = 725195^2 + 4541614^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21152165513021 - 2¹⁸ = 21152165250877 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 (21152165513023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19073366 + ... + 20151863.

It is an arithmetic number, because the mean of its divisors is an integer number (2652115863375).

Almost surely, 2^{21152165513021} is an apocalyptic number.

It is an amenable number.

21152165513021 is a deficient number, since it is larger than the sum of its proper divisors (64761393979).

21152165513021 is a wasteful number, since it uses less digits than its factorization.

21152165513021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39226879.

The product of its (nonzero) digits is 18000, while the sum is 35.

The spelling of 21152165513021 in words is "twenty-one trillion, one hundred fifty-two billion, one hundred sixty-five million, five hundred thirteen thousand, twenty-one".