21270371 has 4 divisors (see below), whose sum is σ = 21956544. Its totient is φ = 20584200.

The previous prime is 21270323. The next prime is 21270373. The reversal of 21270371 is 17307212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21270371 - 2⁶ = 21270307 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21270373) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 343040 + ... + 343101.

It is an arithmetic number, because the mean of its divisors is an integer number (5489136).

Almost surely, 2^21270371 is an apocalyptic number.

21270371 is a deficient number, since it is larger than the sum of its proper divisors (686173).

21270371 is an equidigital number, since it uses as much as digits as its factorization.

21270371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 686172.

The product of its (nonzero) digits is 588, while the sum is 23.

The square root of 21270371 is about 4611.9812445412. The cubic root of 21270371 is about 277.0713931023.

Adding to 21270371 its reverse (17307212), we get a palindrome (38577583).

The spelling of 21270371 in words is "twenty-one million, two hundred seventy thousand, three hundred seventy-one".