21210719 has 2 divisors, whose sum is σ = 21210720. Its totient is φ = 21210718.

The previous prime is 21210703. The next prime is 21210743. The reversal of 21210719 is 91701212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21210719 - 2⁴ = 21210703 is a prime.

It is a super-2 number, since 2×21210719² = 899789200993922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21210694 and 21210703.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21210769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605359 + 10605360.

It is an arithmetic number, because the mean of its divisors is an integer number (10605360).

Almost surely, 2^21210719 is an apocalyptic number.

21210719 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210719 is an equidigital number, since it uses as much as digits as its factorization.

21210719 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 23.

The square root of 21210719 is about 4605.5096352087. The cubic root of 21210719 is about 276.8121383004.

The spelling of 21210719 in words is "twenty-one million, two hundred ten thousand, seven hundred nineteen".