21270547 has 2 divisors, whose sum is σ = 21270548. Its totient is φ = 21270546.

The previous prime is 21270539. The next prime is 21270551. The reversal of 21270547 is 74507212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21270547 - 2³ = 21270539 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (21270527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10635273 + 10635274.

It is an arithmetic number, because the mean of its divisors is an integer number (10635274).

Almost surely, 2^21270547 is an apocalyptic number.

21270547 is a deficient number, since it is larger than the sum of its proper divisors (1).

21270547 is an equidigital number, since it uses as much as digits as its factorization.

21270547 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3920, while the sum is 28.

The square root of 21270547 is about 4612.0003252385. Note that the first 3 decimals coincide. The cubic root of 21270547 is about 277.0721573020.

Adding to 21270547 its reverse (74507212), we get a palindrome (95777759).

The spelling of 21270547 in words is "twenty-one million, two hundred seventy thousand, five hundred forty-seven".