21257003 has 2 divisors, whose sum is σ = 21257004. Its totient is φ = 21257002.

The previous prime is 21256999. The next prime is 21257011. The reversal of 21257003 is 30075212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21257003 - 2² = 21256999 is a prime.

It is not a weakly prime, because it can be changed into another prime (21257053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10628501 + 10628502.

It is an arithmetic number, because the mean of its divisors is an integer number (10628502).

Almost surely, 2^21257003 is an apocalyptic number.

21257003 is a deficient number, since it is larger than the sum of its proper divisors (1).

21257003 is an equidigital number, since it uses as much as digits as its factorization.

21257003 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 420, while the sum is 20.

The square root of 21257003 is about 4610.5317480742. The cubic root of 21257003 is about 277.0133363404.

The spelling of 21257003 in words is "twenty-one million, two hundred fifty-seven thousand, three".