21305166355 has 48 divisors (see below), whose sum is σ = 30269352960. Its totient is φ = 14337449280.

The previous prime is 21305166353. The next prime is 21305166371. The reversal of 21305166355 is 55366150312.

It is not a de Polignac number, because 21305166355 - 2¹ = 21305166353 is a prime.

It is a super-2 number, since 2×21305166355² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21305166353) 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 47 ways as a sum of consecutive naturals, for example, 472734 + ... + 515836.

It is an arithmetic number, because the mean of its divisors is an integer number (630611520).

Almost surely, 2^21305166355 is an apocalyptic number.

21305166355 is a deficient number, since it is larger than the sum of its proper divisors (8964186605).

21305166355 is a wasteful number, since it uses less digits than its factorization.

21305166355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43192 (or 43181 counting only the distinct ones).

The product of its (nonzero) digits is 81000, while the sum is 37.

The spelling of 21305166355 in words is "twenty-one billion, three hundred five million, one hundred sixty-six thousand, three hundred fifty-five".