21573469 has 2 divisors, whose sum is σ = 21573470. Its totient is φ = 21573468.

The previous prime is 21573449. The next prime is 21573509. The reversal of 21573469 is 96437512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21040569 + 532900 = 4587^2 + 730^2 .

It is a cyclic number.

It is not a de Polignac number, because 21573469 - 2⁵ = 21573437 is a prime.

It is a super-2 number, since 2×21573469² = 930829129387922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21573439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10786734 + 10786735.

It is an arithmetic number, because the mean of its divisors is an integer number (10786735).

Almost surely, 2^21573469 is an apocalyptic number.

It is an amenable number.

21573469 is a deficient number, since it is larger than the sum of its proper divisors (1).

21573469 is an equidigital number, since it uses as much as digits as its factorization.

21573469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 37.

The square root of 21573469 is about 4644.7248572978. The cubic root of 21573469 is about 278.3812592322.

The spelling of 21573469 in words is "twenty-one million, five hundred seventy-three thousand, four hundred sixty-nine".