21981419 has 2 divisors, whose sum is σ = 21981420. Its totient is φ = 21981418.

The previous prime is 21981403. The next prime is 21981433. The reversal of 21981419 is 91418912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21981419 - 2⁴ = 21981403 is a prime.

It is a super-2 number, since 2×21981419² = 966365562507122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21981469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10990709 + 10990710.

It is an arithmetic number, because the mean of its divisors is an integer number (10990710).

Almost surely, 2^21981419 is an apocalyptic number.

21981419 is a deficient number, since it is larger than the sum of its proper divisors (1).

21981419 is an equidigital number, since it uses as much as digits as its factorization.

21981419 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 35.

The square root of 21981419 is about 4688.4346001624. The cubic root of 21981419 is about 280.1250249482.

The spelling of 21981419 in words is "twenty-one million, nine hundred eighty-one thousand, four hundred nineteen".