21910025 has 24 divisors (see below), whose sum is σ = 29712384. Its totient is φ = 15955200.

The previous prime is 21910013. The next prime is 21910043. The reversal of 21910025 is 52001912.

It is not a de Polignac number, because 21910025 - 2¹² = 21905929 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21909979 and 21910006.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12344 + ... + 14006.

It is an arithmetic number, because the mean of its divisors is an integer number (1238016).

Almost surely, 2^21910025 is an apocalyptic number.

21910025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21910025 is a deficient number, since it is larger than the sum of its proper divisors (7802359).

21910025 is a wasteful number, since it uses less digits than its factorization.

21910025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1721 (or 1716 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 21910025 is about 4680.8145658635. The cubic root of 21910025 is about 279.8214209937.

Adding to 21910025 its reverse (52001912), we get a palindrome (73911937).

The spelling of 21910025 in words is "twenty-one million, nine hundred ten thousand, twenty-five".