21025619 has 2 divisors, whose sum is σ = 21025620. Its totient is φ = 21025618.

The previous prime is 21025603. The next prime is 21025639. The reversal of 21025619 is 91652012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21025619 - 2⁴ = 21025603 is a prime.

It is a super-2 number, since 2×21025619² = 884153308666322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21025639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10512809 + 10512810.

It is an arithmetic number, because the mean of its divisors is an integer number (10512810).

Almost surely, 2^21025619 is an apocalyptic number.

21025619 is a deficient number, since it is larger than the sum of its proper divisors (1).

21025619 is an equidigital number, since it uses as much as digits as its factorization.

21025619 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 21025619 is about 4585.3701050188. The cubic root of 21025619 is about 276.0045639167.

The spelling of 21025619 in words is "twenty-one million, twenty-five thousand, six hundred nineteen".