21379019 has 2 divisors, whose sum is σ = 21379020. Its totient is φ = 21379018.

The previous prime is 21378997. The next prime is 21379021. The reversal of 21379019 is 91097312.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21379019 - 2¹⁶ = 21313483 is a prime.

It is a super-2 number, since 2×21379019² = 914124906804722, which contains 22 as substring.

Together with 21379021, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21379049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10689509 + 10689510.

It is an arithmetic number, because the mean of its divisors is an integer number (10689510).

Almost surely, 2^21379019 is an apocalyptic number.

21379019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21379019 is an equidigital number, since it uses as much as digits as its factorization.

21379019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3402, while the sum is 32.

The square root of 21379019 is about 4623.7451270588. The cubic root of 21379019 is about 277.5423477833.

The spelling of 21379019 in words is "twenty-one million, three hundred seventy-nine thousand, nineteen".