21240423434 has 8 divisors (see below), whose sum is σ = 31984607268. Its totient is φ = 10578887680.

The previous prime is 21240423431. The next prime is 21240423461. The reversal of 21240423434 is 43432404212.

It can be written as a sum of positive squares in 2 ways, for example, as 20674126225 + 566297209 = 143785^2 + 23797^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21240423397 and 21240423406.

It is not an unprimeable number, because it can be changed into a prime (21240423431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20661377 + ... + 20662404.

Almost surely, 2^21240423434 is an apocalyptic number.

21240423434 is a deficient number, since it is larger than the sum of its proper divisors (10744183834).

21240423434 is a wasteful number, since it uses less digits than its factorization.

21240423434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41324040.

The product of its (nonzero) digits is 18432, while the sum is 29.

Adding to 21240423434 its reverse (43432404212), we get a palindrome (64672827646).

The spelling of 21240423434 in words is "twenty-one billion, two hundred forty million, four hundred twenty-three thousand, four hundred thirty-four".