21982819 has 8 divisors (see below), whose sum is σ = 23517648. Its totient is φ = 20474880.

The previous prime is 21982817. The next prime is 21982843. The reversal of 21982819 is 91828912.

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

It is a cyclic number.

It is not a de Polignac number, because 21982819 - 2¹ = 21982817 is a prime.

It is a super-2 number, since 2×21982819² = 966488662373522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21982817) 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, 5017 + ... + 8314.

It is an arithmetic number, because the mean of its divisors is an integer number (2939706).

Almost surely, 2^21982819 is an apocalyptic number.

21982819 is a deficient number, since it is larger than the sum of its proper divisors (1534829).

21982819 is a wasteful number, since it uses less digits than its factorization.

21982819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13445.

The product of its digits is 20736, while the sum is 40.

The square root of 21982819 is about 4688.5839013502. The cubic root of 21982819 is about 280.1309718907.

It can be divided in two parts, 21982 and 819, that added together give a square (22801 = 151²).

The spelling of 21982819 in words is "twenty-one million, nine hundred eighty-two thousand, eight hundred nineteen".