21420719 has 2 divisors, whose sum is σ = 21420720. Its totient is φ = 21420718.

The previous prime is 21420713. The next prime is 21420761. The reversal of 21420719 is 91702412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21420719 - 2⁴ = 21420703 is a prime.

It is a super-2 number, since 2×21420719² = 917694404953922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21420713) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10710359 + 10710360.

It is an arithmetic number, because the mean of its divisors is an integer number (10710360).

Almost surely, 2^21420719 is an apocalyptic number.

21420719 is a deficient number, since it is larger than the sum of its proper divisors (1).

21420719 is an equidigital number, since it uses as much as digits as its factorization.

21420719 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 21420719 is about 4628.2522619235. The cubic root of 21420719 is about 277.7226803373.

The spelling of 21420719 in words is "twenty-one million, four hundred twenty thousand, seven hundred nineteen".