21242153 has 2 divisors, whose sum is σ = 21242154. Its totient is φ = 21242152.

The previous prime is 21242131. The next prime is 21242191. The reversal of 21242153 is 35124212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13446889 + 7795264 = 3667^2 + 2792^2 .

It is a cyclic number.

It is not a de Polignac number, because 21242153 - 2¹² = 21238057 is a prime.

It is not a weakly prime, because it can be changed into another prime (21241153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621076 + 10621077.

It is an arithmetic number, because the mean of its divisors is an integer number (10621077).

Almost surely, 2^21242153 is an apocalyptic number.

It is an amenable number.

21242153 is a deficient number, since it is larger than the sum of its proper divisors (1).

21242153 is an equidigital number, since it uses as much as digits as its factorization.

21242153 is an evil number, because the sum of its binary digits is even.

The product of its digits is 480, while the sum is 20.

The square root of 21242153 is about 4608.9210234067. The cubic root of 21242153 is about 276.9488147592.

Adding to 21242153 its reverse (35124212), we get a palindrome (56366365).

The spelling of 21242153 in words is "twenty-one million, two hundred forty-two thousand, one hundred fifty-three".