21003434 has 4 divisors (see below), whose sum is σ = 31505154. Its totient is φ = 10501716.

The previous prime is 21003431. The next prime is 21003473. The reversal of 21003434 is 43430012.

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., 15015625 + 5987809 = 3875^2 + 2447^2 .

It is a super-2 number, since 2×21003434² = 882288479584712, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21003431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5250857 + ... + 5250860.

Almost surely, 2^21003434 is an apocalyptic number.

21003434 is a deficient number, since it is larger than the sum of its proper divisors (10501720).

21003434 is a wasteful number, since it uses less digits than its factorization.

21003434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10501719.

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 21003434 is about 4582.9503597573. The cubic root of 21003434 is about 275.9074551449.

Adding to 21003434 its reverse (43430012), we get a palindrome (64433446).

The spelling of 21003434 in words is "twenty-one million, three thousand, four hundred thirty-four".