21535001 has 2 divisors, whose sum is σ = 21535002. Its totient is φ = 21535000.

The previous prime is 21534991. The next prime is 21535027. The reversal of 21535001 is 10053512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20430400 + 1104601 = 4520^2 + 1051^2 .

It is a cyclic number.

It is not a de Polignac number, because 21535001 - 2¹⁰ = 21533977 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21535091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10767500 + 10767501.

It is an arithmetic number, because the mean of its divisors is an integer number (10767501).

Almost surely, 2^21535001 is an apocalyptic number.

It is an amenable number.

21535001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21535001 is an equidigital number, since it uses as much as digits as its factorization.

21535001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 21535001 is about 4640.5819678140. The cubic root of 21535001 is about 278.2156987532.

Adding to 21535001 its reverse (10053512), we get a palindrome (31588513).

The spelling of 21535001 in words is "twenty-one million, five hundred thirty-five thousand, one".