21364434634 has 4 divisors (see below), whose sum is σ = 32046651954. Its totient is φ = 10682217316.

The previous prime is 21364434607. The next prime is 21364434659. The reversal of 21364434634 is 43643446312.

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., 16229995609 + 5134439025 = 127397^2 + 71655^2 .

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 an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5341108657 + ... + 5341108660.

Almost surely, 2^21364434634 is an apocalyptic number.

21364434634 is a deficient number, since it is larger than the sum of its proper divisors (10682217320).

21364434634 is a wasteful number, since it uses less digits than its factorization.

21364434634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10682217319.

The product of its digits is 497664, while the sum is 40.

The spelling of 21364434634 in words is "twenty-one billion, three hundred sixty-four million, four hundred thirty-four thousand, six hundred thirty-four".