21380925 has 12 divisors (see below), whose sum is σ = 35349920. Its totient is φ = 11403120.

The previous prime is 21380923. The next prime is 21380929. The reversal of 21380925 is 52908312.

It is a happy number.

It is not a de Polignac number, because 21380925 - 2¹ = 21380923 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21380892 and 21380901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21380921) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 142465 + ... + 142614.

Almost surely, 2^21380925 is an apocalyptic number.

21380925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21380925 is a deficient number, since it is larger than the sum of its proper divisors (13968995).

21380925 is a wasteful number, since it uses less digits than its factorization.

21380925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285092 (or 285087 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 21380925 is about 4623.9512324418. The cubic root of 21380925 is about 277.5505954333.

The spelling of 21380925 in words is "twenty-one million, three hundred eighty thousand, nine hundred twenty-five".