21221432434 has 4 divisors (see below), whose sum is σ = 31832148654. Its totient is φ = 10610716216.

The previous prime is 21221432417. The next prime is 21221432467. The reversal of 21221432434 is 43423412212.

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

It can be written as a sum of positive squares in only one way, i.e., 21165885225 + 55547209 = 145485^2 + 7453^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5305358107 + ... + 5305358110.

Almost surely, 2^21221432434 is an apocalyptic number.

21221432434 is a deficient number, since it is larger than the sum of its proper divisors (10610716220).

21221432434 is a wasteful number, since it uses less digits than its factorization.

21221432434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10610716219.

The product of its digits is 9216, while the sum is 28.

Adding to 21221432434 its reverse (43423412212), we get a palindrome (64644844646).

The spelling of 21221432434 in words is "twenty-one billion, two hundred twenty-one million, four hundred thirty-two thousand, four hundred thirty-four".