21025371 has 4 divisors (see below), whose sum is σ = 28033832. Its totient is φ = 14016912.

The previous prime is 21025363. The next prime is 21025397. The reversal of 21025371 is 17352012.

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

It is not a de Polignac number, because 21025371 - 2³ = 21025363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21025321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3504226 + ... + 3504231.

It is an arithmetic number, because the mean of its divisors is an integer number (7008458).

Almost surely, 2^21025371 is an apocalyptic number.

21025371 is a deficient number, since it is larger than the sum of its proper divisors (7008461).

21025371 is an equidigital number, since it uses as much as digits as its factorization.

21025371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7008460.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 21025371 is about 4585.3430624109. The cubic root of 21025371 is about 276.0034787421.

Adding to 21025371 its reverse (17352012), we get a palindrome (38377383).

The spelling of 21025371 in words is "twenty-one million, twenty-five thousand, three hundred seventy-one".