21307425 has 24 divisors (see below), whose sum is σ = 35521536. Its totient is φ = 11269440.

The previous prime is 21307423. The next prime is 21307441. The reversal of 21307425 is 52470312.

It is not a de Polignac number, because 21307425 - 2¹ = 21307423 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21307395 and 21307404.

It is not an unprimeable number, because it can be changed into a prime (21307421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8407 + ... + 10643.

It is an arithmetic number, because the mean of its divisors is an integer number (1480064).

Almost surely, 2^21307425 is an apocalyptic number.

21307425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21307425 is a deficient number, since it is larger than the sum of its proper divisors (14214111).

21307425 is a wasteful number, since it uses less digits than its factorization.

21307425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2377 (or 2372 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 21307425 is about 4615.9966421132. The cubic root of 21307425 is about 277.2321902902.

Adding to 21307425 its reverse (52470312), we get a palindrome (73777737).

The spelling of 21307425 in words is "twenty-one million, three hundred seven thousand, four hundred twenty-five".