21503234 has 4 divisors (see below), whose sum is σ = 32254854. Its totient is φ = 10751616.

The previous prime is 21503227. The next prime is 21503263. The reversal of 21503234 is 43230512.

It is a happy number.

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., 17197609 + 4305625 = 4147^2 + 2075^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5375807 + ... + 5375810.

Almost surely, 2^21503234 is an apocalyptic number.

21503234 is a deficient number, since it is larger than the sum of its proper divisors (10751620).

21503234 is a wasteful number, since it uses less digits than its factorization.

21503234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10751619.

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

The square root of 21503234 is about 4637.1579658235. The cubic root of 21503234 is about 278.0788296712.

Adding to 21503234 its reverse (43230512), we get a palindrome (64733746).

The spelling of 21503234 in words is "twenty-one million, five hundred three thousand, two hundred thirty-four".