21745469 has 2 divisors, whose sum is σ = 21745470. Its totient is φ = 21745468.

The previous prime is 21745441. The next prime is 21745483. The reversal of 21745469 is 96454712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19909444 + 1836025 = 4462^2 + 1355^2 .

It is a cyclic number.

It is not a de Polignac number, because 21745469 - 2¹² = 21741373 is a prime.

It is a super-2 number, since 2×21745469² = 945730844059922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21745429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10872734 + 10872735.

It is an arithmetic number, because the mean of its divisors is an integer number (10872735).

Almost surely, 2^21745469 is an apocalyptic number.

It is an amenable number.

21745469 is a deficient number, since it is larger than the sum of its proper divisors (1).

21745469 is an equidigital number, since it uses as much as digits as its factorization.

21745469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 60480, while the sum is 38.

The square root of 21745469 is about 4663.2037270529. The cubic root of 21745469 is about 279.1191236876.

It can be divided in two parts, 2 and 1745469, that added together give a palindrome (1745471).

The spelling of 21745469 in words is "twenty-one million, seven hundred forty-five thousand, four hundred sixty-nine".