21632447 has 2 divisors, whose sum is σ = 21632448. Its totient is φ = 21632446.

The previous prime is 21632417. The next prime is 21632459. The reversal of 21632447 is 74423612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21632447 - 2¹² = 21628351 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21632407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10816223 + 10816224.

It is an arithmetic number, because the mean of its divisors is an integer number (10816224).

Almost surely, 2^21632447 is an apocalyptic number.

21632447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21632447 is an equidigital number, since it uses as much as digits as its factorization.

21632447 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 29.

The square root of 21632447 is about 4651.0694469122. The cubic root of 21632447 is about 278.6347099091.

The spelling of 21632447 in words is "twenty-one million, six hundred thirty-two thousand, four hundred forty-seven".