21694939 has 8 divisors (see below), whose sum is σ = 24837120. Its totient is φ = 18563496.

The previous prime is 21694931. The next prime is 21694951. The reversal of 21694939 is 93949612.

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

It is not a de Polignac number, because 21694939 - 2³ = 21694931 is a prime.

It is a super-3 number, since 3×21694939³ (a number of 23 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21694895 and 21694904.

It is not an unprimeable number, because it can be changed into a prime (21694931) 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, 2262 + ... + 6964.

It is an arithmetic number, because the mean of its divisors is an integer number (3104640).

Almost surely, 2^21694939 is an apocalyptic number.

21694939 is a deficient number, since it is larger than the sum of its proper divisors (3142181).

21694939 is an equidigital number, since it uses as much as digits as its factorization.

21694939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5369.

The product of its digits is 104976, while the sum is 43.

The square root of 21694939 is about 4657.7826269589. The cubic root of 21694939 is about 278.9027594133.

The spelling of 21694939 in words is "twenty-one million, six hundred ninety-four thousand, nine hundred thirty-nine".