21138425 has 48 divisors (see below), whose sum is σ = 33331200. Its totient is φ = 12916800.

The previous prime is 21138421. The next prime is 21138427. The reversal of 21138425 is 52483112.

It is not a de Polignac number, because 21138425 - 2² = 21138421 is a prime.

It is a super-2 number, since 2×21138425² = 893666022961250, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21138394 and 21138403.

It is not an unprimeable number, because it can be changed into a prime (21138421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 152006 + ... + 152144.

It is an arithmetic number, because the mean of its divisors is an integer number (694400).

Almost surely, 2^21138425 is an apocalyptic number.

21138425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21138425 is a deficient number, since it is larger than the sum of its proper divisors (12192775).

21138425 is a wasteful number, since it uses less digits than its factorization.

21138425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246 (or 241 counting only the distinct ones).

The product of its digits is 1920, while the sum is 26.

The square root of 21138425 is about 4597.6542932239. The cubic root of 21138425 is about 276.4972874960.

The spelling of 21138425 in words is "twenty-one million, one hundred thirty-eight thousand, four hundred twenty-five".