21550469 has 2 divisors, whose sum is σ = 21550470. Its totient is φ = 21550468.

The previous prime is 21550457. The next prime is 21550493. The reversal of 21550469 is 96405512.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21436900 + 113569 = 4630^2 + 337^2 .

It is a cyclic number.

It is not a de Polignac number, because 21550469 - 2⁴ = 21550453 is a prime.

It is a super-2 number, since 2×21550469² = 928845428239922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21550409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10775234 + 10775235.

It is an arithmetic number, because the mean of its divisors is an integer number (10775235).

Almost surely, 2^21550469 is an apocalyptic number.

It is an amenable number.

21550469 is a deficient number, since it is larger than the sum of its proper divisors (1).

21550469 is an equidigital number, since it uses as much as digits as its factorization.

21550469 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 21550469 is about 4642.2482699658. The cubic root of 21550469 is about 278.2822943772.

The spelling of 21550469 in words is "twenty-one million, five hundred fifty thousand, four hundred sixty-nine".