21970025 has 48 divisors (see below), whose sum is σ = 34604928. Its totient is φ = 13440000.

The previous prime is 21970021. The next prime is 21970043. The reversal of 21970025 is 52007912.

It is not a de Polignac number, because 21970025 - 2² = 21970021 is a prime.

It is a Smith number, since the sum of its digits (26) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21969976 and 21970003.

It is not an unprimeable number, because it can be changed into a prime (21970021) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 194369 + ... + 194481.

It is an arithmetic number, because the mean of its divisors is an integer number (720936).

Almost surely, 2^21970025 is an apocalyptic number.

21970025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21970025 is a deficient number, since it is larger than the sum of its proper divisors (12634903).

21970025 is a wasteful number, since it uses less digits than its factorization.

21970025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242 (or 237 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 26.

The square root of 21970025 is about 4687.2193249303. The cubic root of 21970025 is about 280.0766159386.

Adding to 21970025 its reverse (52007912), we get a palindrome (73977937).

The spelling of 21970025 in words is "twenty-one million, nine hundred seventy thousand, twenty-five".