21203534 has 16 divisors (see below), whose sum is σ = 34801920. Its totient is φ = 9608760.

The previous prime is 21203513. The next prime is 21203543. The reversal of 21203534 is 43530212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 7067 + ... + 9609.

It is an arithmetic number, because the mean of its divisors is an integer number (2175120).

Almost surely, 2^21203534 is an apocalyptic number.

21203534 is a deficient number, since it is larger than the sum of its proper divisors (13598386).

21203534 is a wasteful number, since it uses less digits than its factorization.

21203534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2935.

The product of its (nonzero) digits is 720, while the sum is 20.

The square root of 21203534 is about 4604.7295251730. The cubic root of 21203534 is about 276.7808786367.

Adding to 21203534 its reverse (43530212), we get a palindrome (64733746).

The spelling of 21203534 in words is "twenty-one million, two hundred three thousand, five hundred thirty-four".