21046217 has 2 divisors, whose sum is σ = 21046218. Its totient is φ = 21046216.

The previous prime is 21046171. The next prime is 21046231. The reversal of 21046217 is 71264012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19855936 + 1190281 = 4456^2 + 1091^2 .

It is a cyclic number.

It is not a de Polignac number, because 21046217 - 2⁸ = 21045961 is a prime.

It is a super-2 number, since 2×21046217² = 885886500022178, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21046192 and 21046201.

It is not a weakly prime, because it can be changed into another prime (21006217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10523108 + 10523109.

It is an arithmetic number, because the mean of its divisors is an integer number (10523109).

Almost surely, 2^21046217 is an apocalyptic number.

It is an amenable number.

21046217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21046217 is an equidigital number, since it uses as much as digits as its factorization.

21046217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 21046217 is about 4587.6156116222. The cubic root of 21046217 is about 276.0946648948.

The spelling of 21046217 in words is "twenty-one million, forty-six thousand, two hundred seventeen".