21710869 has 2 divisors, whose sum is σ = 21710870. Its totient is φ = 21710868.

The previous prime is 21710861. The next prime is 21710917. The reversal of 21710869 is 96801712.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11819844 + 9891025 = 3438^2 + 3145^2 .

It is a cyclic number.

It is not a de Polignac number, because 21710869 - 2³ = 21710861 is a prime.

It is a super-2 number, since 2×21710869² = 942723665470322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21710861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10855434 + 10855435.

It is an arithmetic number, because the mean of its divisors is an integer number (10855435).

Almost surely, 2^21710869 is an apocalyptic number.

It is an amenable number.

21710869 is a deficient number, since it is larger than the sum of its proper divisors (1).

21710869 is an equidigital number, since it uses as much as digits as its factorization.

21710869 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 21710869 is about 4659.4923543236. The cubic root of 21710869 is about 278.9710062667.

The spelling of 21710869 in words is "twenty-one million, seven hundred ten thousand, eight hundred sixty-nine".