21125619 has 12 divisors (see below), whose sum is σ = 31259592. Its totient is φ = 13740000.

The previous prime is 21125603. The next prime is 21125623. The reversal of 21125619 is 91652112.

21125619 is a `hidden beast` number, since 21 + 1 + 25 + 619 = 666.

It is not a de Polignac number, because 21125619 - 2⁴ = 21125603 is a prime.

It is a super-2 number, since 2×21125619² = 892583556266322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21125592 and 21125601.

It is not an unprimeable number, because it can be changed into a prime (21125639) 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 11 ways as a sum of consecutive naturals, for example, 28257 + ... + 28994.

It is an arithmetic number, because the mean of its divisors is an integer number (2604966).

Almost surely, 2^21125619 is an apocalyptic number.

21125619 is a deficient number, since it is larger than the sum of its proper divisors (10133973).

21125619 is a wasteful number, since it uses less digits than its factorization.

21125619 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57298 (or 57295 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 21125619 is about 4596.2614155420. The cubic root of 21125619 is about 276.4414407062.

The spelling of 21125619 in words is "twenty-one million, one hundred twenty-five thousand, six hundred nineteen".