21030001 has 2 divisors, whose sum is σ = 21030002. Its totient is φ = 21030000.

The previous prime is 21029977. The next prime is 21030043. The reversal of 21030001 is 10003012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17438976 + 3591025 = 4176^2 + 1895^2 .

It is a cyclic number.

It is not a de Polignac number, because 21030001 - 2¹⁹ = 20505713 is a prime.

It is not a weakly prime, because it can be changed into another prime (21030301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10515000 + 10515001.

It is an arithmetic number, because the mean of its divisors is an integer number (10515001).

Almost surely, 2^21030001 is an apocalyptic number.

It is an amenable number.

21030001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21030001 is an equidigital number, since it uses as much as digits as its factorization.

21030001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6, while the sum is 7.

The square root of 21030001 is about 4585.8479041503. The cubic root of 21030001 is about 276.0237368439.

Adding to 21030001 its reverse (10003012), we get a palindrome (31033013).

The spelling of 21030001 in words is "twenty-one million, thirty thousand, one".