21647453 has 2 divisors, whose sum is σ = 21647454. Its totient is φ = 21647452.

The previous prime is 21647429. The next prime is 21647471. The reversal of 21647453 is 35474612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19695844 + 1951609 = 4438^2 + 1397^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21647453 is a prime.

It is a super-2 number, since 2×21647453² = 937224442774418, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21647413) 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, 10823726 + 10823727.

It is an arithmetic number, because the mean of its divisors is an integer number (10823727).

Almost surely, 2^21647453 is an apocalyptic number.

It is an amenable number.

21647453 is a deficient number, since it is larger than the sum of its proper divisors (1).

21647453 is an equidigital number, since it uses as much as digits as its factorization.

21647453 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20160, while the sum is 32.

The square root of 21647453 is about 4652.6823446266. The cubic root of 21647453 is about 278.6991228105.

The spelling of 21647453 in words is "twenty-one million, six hundred forty-seven thousand, four hundred fifty-three".