21355355531601 has 64 divisors (see below), whose sum is σ = 38939403417600. Its totient is φ = 11264113585728.

The previous prime is 21355355531557. The next prime is 21355355531603. The reversal of 21355355531601 is 10613555355312.

21355355531601 is a `hidden beast` number, since 2 + 1 + 3 + 5 + 5 + 3 + 5 + 5 + 5 + 31 + 601 = 666.

It is not a de Polignac number, because 21355355531601 - 2¹⁰ = 21355355530577 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21355355531603) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 176811690 + ... + 176932428.

It is an arithmetic number, because the mean of its divisors is an integer number (608428178400).

Almost surely, 2^{21355355531601} is an apocalyptic number.

21355355531601 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21355355531601 is a deficient number, since it is larger than the sum of its proper divisors (17584047885999).

21355355531601 is a wasteful number, since it uses less digits than its factorization.

21355355531601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192755 (or 192749 counting only the distinct ones).

The product of its (nonzero) digits is 1012500, while the sum is 45.

The spelling of 21355355531601 in words is "twenty-one trillion, three hundred fifty-five billion, three hundred fifty-five million, five hundred thirty-one thousand, six hundred one".