21510469 has 2 divisors, whose sum is σ = 21510470. Its totient is φ = 21510468.

The previous prime is 21510427. The next prime is 21510479. The reversal of 21510469 is 96401512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18576100 + 2934369 = 4310^2 + 1713^2 .

It is a cyclic number.

It is not a de Polignac number, because 21510469 - 2¹⁹ = 20986181 is a prime.

It is a super-2 number, since 2×21510469² = 925400553199922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21510479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10755234 + 10755235.

It is an arithmetic number, because the mean of its divisors is an integer number (10755235).

Almost surely, 2^21510469 is an apocalyptic number.

It is an amenable number.

21510469 is a deficient number, since it is larger than the sum of its proper divisors (1).

21510469 is an equidigital number, since it uses as much as digits as its factorization.

21510469 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 21510469 is about 4637.9380116599. The cubic root of 21510469 is about 278.1100137361.

The spelling of 21510469 in words is "twenty-one million, five hundred ten thousand, four hundred sixty-nine".