21411391 has 8 divisors (see below), whose sum is σ = 21821744. Its totient is φ = 21003840.

The previous prime is 21411361. The next prime is 21411407. The reversal of 21411391 is 19311412.

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 21411391 - 2⁷ = 21411263 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 (21411301) 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, 20461 + ... + 21481.

It is an arithmetic number, because the mean of its divisors is an integer number (2727718).

Almost surely, 2^21411391 is an apocalyptic number.

21411391 is a deficient number, since it is larger than the sum of its proper divisors (410353).

21411391 is a wasteful number, since it uses less digits than its factorization.

21411391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1401.

The product of its digits is 216, while the sum is 22.

The square root of 21411391 is about 4627.2444283828. The cubic root of 21411391 is about 277.6823615336.

The spelling of 21411391 in words is "twenty-one million, four hundred eleven thousand, three hundred ninety-one".