21550025 has 12 divisors (see below), whose sum is σ = 30539712. Its totient is φ = 14777040.

The previous prime is 21550007. The next prime is 21550043. The reversal of 21550025 is 52005512.

It is an interprime number because it is at equal distance from previous prime (21550007) and next prime (21550043).

It is not a de Polignac number, because 21550025 - 2⁶ = 21549961 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21549979 and 21550006.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 61397 + ... + 61746.

It is an arithmetic number, because the mean of its divisors is an integer number (2544976).

Almost surely, 2^21550025 is an apocalyptic number.

21550025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21550025 is a deficient number, since it is larger than the sum of its proper divisors (8989687).

21550025 is a wasteful number, since it uses less digits than its factorization.

21550025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123160 (or 123155 counting only the distinct ones).

The product of its (nonzero) digits is 500, while the sum is 20.

The square root of 21550025 is about 4642.2004480634. The cubic root of 21550025 is about 278.2803832326.

Adding to 21550025 its reverse (52005512), we get a palindrome (73555537).

The spelling of 21550025 in words is "twenty-one million, five hundred fifty thousand, twenty-five".