21146543462521 has 8 divisors (see below), whose sum is σ = 21185254697544. Its totient is φ = 21107834903040.

The previous prime is 21146543462461. The next prime is 21146543462531. The reversal of 21146543462521 is 12526434564112.

It can be written as a sum of positive squares in 4 ways, for example, as 1323247605625 + 19823295856896 = 1150325^2 + 4452336^2 .

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 21146543462521 - 2³¹ = 21144395978873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21146543462531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15510601 + ... + 16818793.

It is an arithmetic number, because the mean of its divisors is an integer number (2648156837193).

Almost surely, 2^{21146543462521} is an apocalyptic number.

It is an amenable number.

21146543462521 is a deficient number, since it is larger than the sum of its proper divisors (38711235023).

21146543462521 is a wasteful number, since it uses less digits than its factorization.

21146543462521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1337771.

The product of its digits is 1382400, while the sum is 46.

The spelling of 21146543462521 in words is "twenty-one trillion, one hundred forty-six billion, five hundred forty-three million, four hundred sixty-two thousand, five hundred twenty-one".