21115425 has 12 divisors (see below), whose sum is σ = 34910960. Its totient is φ = 11261520.

The previous prime is 21115421. The next prime is 21115427. The reversal of 21115425 is 52451112.

It is not a de Polignac number, because 21115425 - 2² = 21115421 is a prime.

It is a super-2 number, since 2×21115425² = 891722345861250, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21115421) 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, 140695 + ... + 140844.

Almost surely, 2^21115425 is an apocalyptic number.

21115425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21115425 is a deficient number, since it is larger than the sum of its proper divisors (13795535).

21115425 is a wasteful number, since it uses less digits than its factorization.

21115425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281552 (or 281547 counting only the distinct ones).

The product of its digits is 400, while the sum is 21.

The square root of 21115425 is about 4595.1523369743. The cubic root of 21115425 is about 276.3969686769.

Adding to 21115425 its reverse (52451112), we get a palindrome (73566537).

The spelling of 21115425 in words is "twenty-one million, one hundred fifteen thousand, four hundred twenty-five".