21256430230161 has 48 divisors (see below), whose sum is σ = 37154626299648. Its totient is φ = 11431866700800.

The previous prime is 21256430230159. The next prime is 21256430230213. The reversal of 21256430230161 is 16103203465212.

21256430230161 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 643 + 0 + 2 + 3 + 0 + 1 + 6 + 1 = 666.

It is not a de Polignac number, because 21256430230161 - 2¹ = 21256430230159 is a prime.

It is a super-2 number, since 2×21256430230161² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21256430232161) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 137343741 + ... + 137498421.

It is an arithmetic number, because the mean of its divisors is an integer number (774054714576).

Almost surely, 2^{21256430230161} is an apocalyptic number.

21256430230161 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21256430230161 is a deficient number, since it is larger than the sum of its proper divisors (15898196069487).

21256430230161 is a wasteful number, since it uses less digits than its factorization.

21256430230161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283022 (or 283019 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

Adding to 21256430230161 its reverse (16103203465212), we get a palindrome (37359633695373).

The spelling of 21256430230161 in words is "twenty-one trillion, two hundred fifty-six billion, four hundred thirty million, two hundred thirty thousand, one hundred sixty-one".