21071625 has 32 divisors (see below), whose sum is σ = 35538048. Its totient is φ = 11086400.

The previous prime is 21071621. The next prime is 21071641. The reversal of 21071625 is 52617012.

It is not a de Polignac number, because 21071625 - 2² = 21071621 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21071595 and 21071604.

It is not an unprimeable number, because it can be changed into a prime (21071621) 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, 30787 + ... + 31463.

It is an arithmetic number, because the mean of its divisors is an integer number (1110564).

Almost surely, 2^21071625 is an apocalyptic number.

21071625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21071625 is a deficient number, since it is larger than the sum of its proper divisors (14466423).

21071625 is an equidigital number, since it uses as much as digits as its factorization.

21071625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 778 (or 768 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 24.

The square root of 21071625 is about 4590.3839708678. The cubic root of 21071625 is about 276.2057251103.

Adding to 21071625 its reverse (52617012), we get a palindrome (73688637).

The spelling of 21071625 in words is "twenty-one million, seventy-one thousand, six hundred twenty-five".