21270543 has 32 divisors (see below), whose sum is σ = 34214400. Its totient is φ = 11496576.

The previous prime is 21270539. The next prime is 21270547. The reversal of 21270543 is 34507212.

It is a Cunningham number, because it is equal to 4612²-1.

It is an interprime number because it is at equal distance from previous prime (21270539) and next prime (21270547).

It is not a de Polignac number, because 21270543 - 2² = 21270539 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21270547) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 31948 + ... + 32606.

It is an arithmetic number, because the mean of its divisors is an integer number (1069200).

Almost surely, 2^21270543 is an apocalyptic number.

21270543 is a deficient number, since it is larger than the sum of its proper divisors (12943857).

21270543 is a wasteful number, since it uses less digits than its factorization.

21270543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 751.

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 21270543 is about 4611.9998915872. Note that the first 3 decimals coincide. The cubic root of 21270543 is about 277.0721399339.

Adding to 21270543 its reverse (34507212), we get a palindrome (55777755).

The spelling of 21270543 in words is "twenty-one million, two hundred seventy thousand, five hundred forty-three".