21234126577 has 4 divisors (see below), whose sum is σ = 21444365556. Its totient is φ = 21023887600.

The previous prime is 21234126559. The next prime is 21234126593. The reversal of 21234126577 is 77562143212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9698507361 + 11535619216 = 98481^2 + 107404^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21234126577 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21234126377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105119338 + ... + 105119539.

It is an arithmetic number, because the mean of its divisors is an integer number (5361091389).

Almost surely, 2^21234126577 is an apocalyptic number.

It is an amenable number.

21234126577 is a deficient number, since it is larger than the sum of its proper divisors (210238979).

21234126577 is a wasteful number, since it uses less digits than its factorization.

21234126577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210238978.

The product of its digits is 141120, while the sum is 40.

Adding to 21234126577 its reverse (77562143212), we get a palindrome (98796269789).

The spelling of 21234126577 in words is "twenty-one billion, two hundred thirty-four million, one hundred twenty-six thousand, five hundred seventy-seven".