21439693 has 8 divisors (see below), whose sum is σ = 24143616. Its totient is φ = 18861600.

The previous prime is 21439673. The next prime is 21439699. The reversal of 21439693 is 39693412.

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 21439693 - 2²¹ = 19342541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21439699) 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, 31096 + ... + 31777.

It is an arithmetic number, because the mean of its divisors is an integer number (3017952).

Almost surely, 2^21439693 is an apocalyptic number.

It is an amenable number.

21439693 is a deficient number, since it is larger than the sum of its proper divisors (2703923).

21439693 is a wasteful number, since it uses less digits than its factorization.

21439693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62915.

The product of its digits is 34992, while the sum is 37.

The square root of 21439693 is about 4630.3016100466. The cubic root of 21439693 is about 277.8046563443.

The spelling of 21439693 in words is "twenty-one million, four hundred thirty-nine thousand, six hundred ninety-three".