21994837 has 8 divisors (see below), whose sum is σ = 23414400. Its totient is φ = 20601504.

The previous prime is 21994829. The next prime is 21994849. The reversal of 21994837 is 73849912.

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 21994837 - 2³ = 21994829 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21994793 and 21994802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21994807) 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, 4813 + ... + 8194.

It is an arithmetic number, because the mean of its divisors is an integer number (2926800).

Almost surely, 2^21994837 is an apocalyptic number.

It is an amenable number.

21994837 is a deficient number, since it is larger than the sum of its proper divisors (1419563).

21994837 is a wasteful number, since it uses less digits than its factorization.

21994837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13115.

The product of its digits is 108864, while the sum is 43.

The square root of 21994837 is about 4689.8653498795. The cubic root of 21994837 is about 280.1820117611.

The spelling of 21994837 in words is "twenty-one million, nine hundred ninety-four thousand, eight hundred thirty-seven".