21140906 has 8 divisors (see below), whose sum is σ = 31921824. Its totient is φ = 10500300.

The previous prime is 21140897. The next prime is 21140909. The reversal of 21140906 is 60904112.

It is a happy number.

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

It is a zygodrome in base 4.

It is not an unprimeable number, because it can be changed into a prime (21140909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34700 + ... + 35303.

It is an arithmetic number, because the mean of its divisors is an integer number (3990228).

Almost surely, 2^21140906 is an apocalyptic number.

21140906 is a deficient number, since it is larger than the sum of its proper divisors (10780918).

21140906 is a wasteful number, since it uses less digits than its factorization.

21140906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70156.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21140906 is about 4597.9240968072. The cubic root of 21140906 is about 276.5081044945.

The spelling of 21140906 in words is "twenty-one million, one hundred forty thousand, nine hundred six".