21345406 has 8 divisors (see below), whose sum is σ = 32222520. Its totient is φ = 10604568.

The previous prime is 21345397. The next prime is 21345409. The reversal of 21345406 is 60454312.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21345409) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33676 + ... + 34303.

It is an arithmetic number, because the mean of its divisors is an integer number (4027815).

Almost surely, 2^21345406 is an apocalyptic number.

21345406 is a deficient number, since it is larger than the sum of its proper divisors (10877114).

21345406 is a wasteful number, since it uses less digits than its factorization.

21345406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68138.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 21345406 is about 4620.1088731760. The cubic root of 21345406 is about 277.3968168717.

Adding to 21345406 its reverse (60454312), we get a palindrome (81799718).

The spelling of 21345406 in words is "twenty-one million, three hundred forty-five thousand, four hundred six".