21272047 has 2 divisors, whose sum is σ = 21272048. Its totient is φ = 21272046.

The previous prime is 21272023. The next prime is 21272099. The reversal of 21272047 is 74027212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21272047 - 2²³ = 12883439 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21272947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10636023 + 10636024.

It is an arithmetic number, because the mean of its divisors is an integer number (10636024).

Almost surely, 2^21272047 is an apocalyptic number.

21272047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21272047 is an equidigital number, since it uses as much as digits as its factorization.

21272047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1568, while the sum is 25.

The square root of 21272047 is about 4612.1629416143. The cubic root of 21272047 is about 277.0786701962.

Adding to 21272047 its reverse (74027212), we get a palindrome (95299259).

The spelling of 21272047 in words is "twenty-one million, two hundred seventy-two thousand, forty-seven".