21447469 has 4 divisors (see below), whose sum is σ = 21970620. Its totient is φ = 20924320.

The previous prime is 21447427. The next prime is 21447509. The reversal of 21447469 is 96474412.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8037225 + 13410244 = 2835^2 + 3662^2 .

It is a cyclic number.

It is not a de Polignac number, because 21447469 - 2⁷ = 21447341 is a prime.

It is a super-2 number, since 2×21447469² = 919987853011922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21447869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 261514 + ... + 261595.

It is an arithmetic number, because the mean of its divisors is an integer number (5492655).

Almost surely, 2^21447469 is an apocalyptic number.

It is an amenable number.

21447469 is a deficient number, since it is larger than the sum of its proper divisors (523151).

21447469 is an equidigital number, since it uses as much as digits as its factorization.

21447469 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 523150.

The product of its digits is 48384, while the sum is 37.

The square root of 21447469 is about 4631.1412200450. The cubic root of 21447469 is about 277.8382381046.

The spelling of 21447469 in words is "twenty-one million, four hundred forty-seven thousand, four hundred sixty-nine".