21270539 has 2 divisors, whose sum is σ = 21270540. Its totient is φ = 21270538.

The previous prime is 21270533. The next prime is 21270547. The reversal of 21270539 is 93507212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21270539 - 2²⁰ = 20221963 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21270533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10635269 + 10635270.

It is an arithmetic number, because the mean of its divisors is an integer number (10635270).

Almost surely, 2^21270539 is an apocalyptic number.

21270539 is a deficient number, since it is larger than the sum of its proper divisors (1).

21270539 is an equidigital number, since it uses as much as digits as its factorization.

21270539 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3780, while the sum is 29.

The square root of 21270539 is about 4611.9994579358. Note that the first 3 decimals coincide. The cubic root of 21270539 is about 277.0721225657.

The spelling of 21270539 in words is "twenty-one million, two hundred seventy thousand, five hundred thirty-nine".