21532306 has 4 divisors (see below), whose sum is σ = 32298462. Its totient is φ = 10766152.

The previous prime is 21532289. The next prime is 21532307. The reversal of 21532306 is 60323512.

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., 15327225 + 6205081 = 3915^2 + 2491^2 .

It is not an unprimeable number, because it can be changed into a prime (21532307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5383075 + ... + 5383078.

Almost surely, 2^21532306 is an apocalyptic number.

21532306 is a deficient number, since it is larger than the sum of its proper divisors (10766156).

21532306 is a wasteful number, since it uses less digits than its factorization.

21532306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10766155.

The product of its (nonzero) digits is 1080, while the sum is 22.

The square root of 21532306 is about 4640.2915856657. The cubic root of 21532306 is about 278.2040924912.

Adding to 21532306 its reverse (60323512), we get a palindrome (81855818).

The spelling of 21532306 in words is "twenty-one million, five hundred thirty-two thousand, three hundred six".