21234175551 has 12 divisors (see below), whose sum is σ = 30762604912. Its totient is φ = 14114108736.

The previous prime is 21234175537. The next prime is 21234175583. The reversal of 21234175551 is 15557143212.

21234175551 is a `hidden beast` number, since 2 + 1 + 2 + 34 + 1 + 75 + 551 = 666.

It is not a de Polignac number, because 21234175551 - 2⁷ = 21234175423 is a prime.

It is a super-2 number, since 2×21234175551² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21234175351) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3497491 + ... + 3503556.

Almost surely, 2^21234175551 is an apocalyptic number.

21234175551 is a deficient number, since it is larger than the sum of its proper divisors (9528429361).

21234175551 is a wasteful number, since it uses less digits than its factorization.

21234175551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7001390 (or 7001387 counting only the distinct ones).

The product of its digits is 42000, while the sum is 36.

The spelling of 21234175551 in words is "twenty-one billion, two hundred thirty-four million, one hundred seventy-five thousand, five hundred fifty-one".