21723469 has 2 divisors, whose sum is σ = 21723470. Its totient is φ = 21723468.

The previous prime is 21723463. The next prime is 21723539. The reversal of 21723469 is 96432712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20820969 + 902500 = 4563^2 + 950^2 .

It is a cyclic number.

It is not a de Polignac number, because 21723469 - 2¹³ = 21715277 is a prime.

It is a super-3 number, since 3×21723469³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21723463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10861734 + 10861735.

It is an arithmetic number, because the mean of its divisors is an integer number (10861735).

Almost surely, 2^21723469 is an apocalyptic number.

It is an amenable number.

21723469 is a deficient number, since it is larger than the sum of its proper divisors (1).

21723469 is an equidigital number, since it uses as much as digits as its factorization.

21723469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 34.

The square root of 21723469 is about 4660.8442368309. The cubic root of 21723469 is about 279.0249631873.

The spelling of 21723469 in words is "twenty-one million, seven hundred twenty-three thousand, four hundred sixty-nine".