21454541 has 2 divisors, whose sum is σ = 21454542. Its totient is φ = 21454540.

The previous prime is 21454483. The next prime is 21454547. The reversal of 21454541 is 14545412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12752041 + 8702500 = 3571^2 + 2950^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21454541 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 21454541.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21454547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10727270 + 10727271.

It is an arithmetic number, because the mean of its divisors is an integer number (10727271).

Almost surely, 2^21454541 is an apocalyptic number.

It is an amenable number.

21454541 is a deficient number, since it is larger than the sum of its proper divisors (1).

21454541 is an equidigital number, since it uses as much as digits as its factorization.

21454541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3200, while the sum is 26.

The square root of 21454541 is about 4631.9046838207. The cubic root of 21454541 is about 277.8687724938.

Adding to 21454541 its reverse (14545412), we get a palindrome (35999953).

The spelling of 21454541 in words is "twenty-one million, four hundred fifty-four thousand, five hundred forty-one".