21001153 has 2 divisors, whose sum is σ = 21001154. Its totient is φ = 21001152.

The previous prime is 21001121. The next prime is 21001177. The reversal of 21001153 is 35110012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20903184 + 97969 = 4572^2 + 313^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001153 - 2⁵ = 21001121 is a prime.

It is not a weakly prime, because it can be changed into another prime (21004153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500576 + 10500577.

It is an arithmetic number, because the mean of its divisors is an integer number (10500577).

Almost surely, 2^21001153 is an apocalyptic number.

It is an amenable number.

21001153 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001153 is an equidigital number, since it uses as much as digits as its factorization.

21001153 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30, while the sum is 13.

The square root of 21001153 is about 4582.7014958428. The cubic root of 21001153 is about 275.8974668149.

Adding to 21001153 its reverse (35110012), we get a palindrome (56111165).

The spelling of 21001153 in words is "twenty-one million, one thousand, one hundred fifty-three".