21819395 has 16 divisors (see below), whose sum is σ = 28664832. Its totient is φ = 15845760.

The previous prime is 21819383. The next prime is 21819403. The reversal of 21819395 is 59391812.

It is not a de Polignac number, because 21819395 - 2⁶ = 21819331 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1214 + ... + 6716.

It is an arithmetic number, because the mean of its divisors is an integer number (1791552).

Almost surely, 2^21819395 is an apocalyptic number.

21819395 is a deficient number, since it is larger than the sum of its proper divisors (6845437).

21819395 is a wasteful number, since it uses less digits than its factorization.

21819395 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5582.

The product of its digits is 19440, while the sum is 38.

The square root of 21819395 is about 4671.1235265191. The cubic root of 21819395 is about 279.4350641675.

The spelling of 21819395 in words is "twenty-one million, eight hundred nineteen thousand, three hundred ninety-five".