21939386 has 16 divisors (see below), whose sum is σ = 38249280. Its totient is φ = 9242880.

The previous prime is 21939383. The next prime is 21939391. The reversal of 21939386 is 68393912.

It is a super-3 number, since 3×21939386³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21939383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12455 + ... + 14106.

It is an arithmetic number, because the mean of its divisors is an integer number (2390580).

Almost surely, 2^21939386 is an apocalyptic number.

21939386 is a deficient number, since it is larger than the sum of its proper divisors (16309894).

21939386 is a wasteful number, since it uses less digits than its factorization.

21939386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26629.

The product of its digits is 69984, while the sum is 41.

The square root of 21939386 is about 4683.9498289371. The cubic root of 21939386 is about 279.9463587719.

The spelling of 21939386 in words is "twenty-one million, nine hundred thirty-nine thousand, three hundred eighty-six".