21017425 has 24 divisors (see below), whose sum is σ = 30623040. Its totient is φ = 14107200.

The previous prime is 21017419. The next prime is 21017453. The reversal of 21017425 is 52471012.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-21017425 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21017396 and 21017405.

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, 636 + ... + 6514.

It is an arithmetic number, because the mean of its divisors is an integer number (1275960).

Almost surely, 2^21017425 is an apocalyptic number.

21017425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21017425 is a deficient number, since it is larger than the sum of its proper divisors (9605615).

21017425 is a wasteful number, since it uses less digits than its factorization.

21017425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5913 (or 5908 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 21017425 is about 4584.4765240974. The cubic root of 21017425 is about 275.9687048812.

Adding to 21017425 its reverse (52471012), we get a palindrome (73488437).

The spelling of 21017425 in words is "twenty-one million, seventeen thousand, four hundred twenty-five".