21550434354351 has 24 divisors (see below), whose sum is σ = 35576232252704. Its totient is φ = 12314218207680.

The previous prime is 21550434354347. The next prime is 21550434354359. The reversal of 21550434354351 is 15345343405512.

21550434354351 is a `hidden beast` number, since 2 + 1 + 5 + 50 + 4 + 3 + 4 + 3 + 543 + 51 = 666.

It is not a de Polignac number, because 21550434354351 - 2² = 21550434354347 is a prime.

It is a super-2 number, since 2×21550434354351² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21550434354297 and 21550434354306.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21550434354359) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1896856 + ... + 6833661.

Almost surely, 2^{21550434354351} is an apocalyptic number.

21550434354351 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21550434354351 is a deficient number, since it is larger than the sum of its proper divisors (14025797898353).

21550434354351 is a wasteful number, since it uses less digits than its factorization.

21550434354351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8769711 (or 8769708 counting only the distinct ones).

The product of its (nonzero) digits is 2160000, while the sum is 45.

Adding to 21550434354351 its reverse (15345343405512), we get a palindrome (36895777759863).

The spelling of 21550434354351 in words is "twenty-one trillion, five hundred fifty billion, four hundred thirty-four million, three hundred fifty-four thousand, three hundred fifty-one".