21550453 has 2 divisors, whose sum is σ = 21550454. Its totient is φ = 21550452.

The previous prime is 21550447. The next prime is 21550457. The reversal of 21550453 is 35405512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10909809 + 10640644 = 3303^2 + 3262^2 .

It is a cyclic number.

It is not a de Polignac number, because 21550453 - 2¹⁷ = 21419381 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21550457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10775226 + 10775227.

It is an arithmetic number, because the mean of its divisors is an integer number (10775227).

Almost surely, 2^21550453 is an apocalyptic number.

It is an amenable number.

21550453 is a deficient number, since it is larger than the sum of its proper divisors (1).

21550453 is an equidigital number, since it uses as much as digits as its factorization.

21550453 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3000, while the sum is 25.

The square root of 21550453 is about 4642.2465466625. The cubic root of 21550453 is about 278.2822255076.

Adding to 21550453 its reverse (35405512), we get a palindrome (56955965).

The spelling of 21550453 in words is "twenty-one million, five hundred fifty thousand, four hundred fifty-three".