21109407 has 8 divisors (see below), whose sum is σ = 30704640. Its totient is φ = 12793560.

The previous prime is 21109397. The next prime is 21109409. The reversal of 21109407 is 70490112.

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

It is not a de Polignac number, because 21109407 - 2⁴ = 21109391 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21109409) 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, 319807 + ... + 319872.

It is an arithmetic number, because the mean of its divisors is an integer number (3838080).

Almost surely, 2^21109407 is an apocalyptic number.

21109407 is a deficient number, since it is larger than the sum of its proper divisors (9595233).

21109407 is a wasteful number, since it uses less digits than its factorization.

21109407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 639693.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 21109407 is about 4594.4974698002. The cubic root of 21109407 is about 276.3707080166.

Adding to 21109407 its reverse (70490112), we get a palindrome (91599519).

The spelling of 21109407 in words is "twenty-one million, one hundred nine thousand, four hundred seven".