21356211475457 has 8 divisors (see below), whose sum is σ = 21367631050920. Its totient is φ = 21344794490880.

The previous prime is 21356211475451. The next prime is 21356211475481. The reversal of 21356211475457 is 75457411265312.

It can be written as a sum of positive squares in 4 ways, for example, as 298841528896 + 21057369946561 = 546664^2 + 4588831^2 .

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 21356211475457 - 2¹⁸ = 21356211213313 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21356211475399 and 21356211475408.

It is not an unprimeable number, because it can be changed into a prime (21356211475451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15955907 + ... + 17242487.

It is an arithmetic number, because the mean of its divisors is an integer number (2670953881365).

Almost surely, 2^{21356211475457} is an apocalyptic number.

It is an amenable number.

21356211475457 is a deficient number, since it is larger than the sum of its proper divisors (11419575463).

21356211475457 is a wasteful number, since it uses less digits than its factorization.

21356211475457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1295443.

The product of its digits is 7056000, while the sum is 53.

The spelling of 21356211475457 in words is "twenty-one trillion, three hundred fifty-six billion, two hundred eleven million, four hundred seventy-five thousand, four hundred fifty-seven".