21820719 has 8 divisors (see below), whose sum is σ = 29175040. Its totient is φ = 14506776.

The previous prime is 21820709. The next prime is 21820751. The reversal of 21820719 is 91702812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21820719 - 2⁴ = 21820703 is a prime.

It is a super-2 number, since 2×21820719² = 952287555353922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21820709) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8809 + ... + 11010.

It is an arithmetic number, because the mean of its divisors is an integer number (3646880).

Almost surely, 2^21820719 is an apocalyptic number.

21820719 is a deficient number, since it is larger than the sum of its proper divisors (7354321).

21820719 is a wasteful number, since it uses less digits than its factorization.

21820719 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20189.

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 21820719 is about 4671.2652461619. The cubic root of 21820719 is about 279.4407160893.

The spelling of 21820719 in words is "twenty-one million, eight hundred twenty thousand, seven hundred nineteen".