21162541 has 2 divisors, whose sum is σ = 21162542. Its totient is φ = 21162540.

The previous prime is 21162539. The next prime is 21162551. The reversal of 21162541 is 14526112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18957316 + 2205225 = 4354^2 + 1485^2 .

It is a cyclic number.

It is not a de Polignac number, because 21162541 - 2¹ = 21162539 is a prime.

Together with 21162539, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21162521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10581270 + 10581271.

It is an arithmetic number, because the mean of its divisors is an integer number (10581271).

Almost surely, 2^21162541 is an apocalyptic number.

It is an amenable number.

21162541 is a deficient number, since it is larger than the sum of its proper divisors (1).

21162541 is an equidigital number, since it uses as much as digits as its factorization.

21162541 is an evil number, because the sum of its binary digits is even.

The product of its digits is 480, while the sum is 22.

The square root of 21162541 is about 4600.2761873609. The cubic root of 21162541 is about 276.6023958383.

Adding to 21162541 its reverse (14526112), we get a palindrome (35688653).

The spelling of 21162541 in words is "twenty-one million, one hundred sixty-two thousand, five hundred forty-one".