21054569 has 2 divisors, whose sum is σ = 21054570. Its totient is φ = 21054568.

The previous prime is 21054559. The next prime is 21054601. The reversal of 21054569 is 96545012.

It is a happy number.

It is an a-pointer prime, because the next prime (21054601) can be obtained adding 21054569 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11812969 + 9241600 = 3437^2 + 3040^2 .

It is a cyclic number.

It is not a de Polignac number, because 21054569 - 2¹² = 21050473 is a prime.

It is a super-2 number, since 2×21054569² = 886589751551522, which contains 22 as substring.

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

It is not a weakly prime, because it can be changed into another prime (21054559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10527284 + 10527285.

It is an arithmetic number, because the mean of its divisors is an integer number (10527285).

Almost surely, 2^21054569 is an apocalyptic number.

It is an amenable number.

21054569 is a deficient number, since it is larger than the sum of its proper divisors (1).

21054569 is an equidigital number, since it uses as much as digits as its factorization.

21054569 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 21054569 is about 4588.5257981186. The cubic root of 21054569 is about 276.1311819512.

The spelling of 21054569 in words is "twenty-one million, fifty-four thousand, five hundred sixty-nine".