21146918 has 8 divisors (see below), whose sum is σ = 34160448. Its totient is φ = 9760104.

The previous prime is 21146911. The next prime is 21146921. The reversal of 21146918 is 81964112.

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 (21146911) 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, 406646 + ... + 406697.

It is an arithmetic number, because the mean of its divisors is an integer number (4270056).

Almost surely, 2^21146918 is an apocalyptic number.

21146918 is a deficient number, since it is larger than the sum of its proper divisors (13013530).

21146918 is a wasteful number, since it uses less digits than its factorization.

21146918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 813358.

The product of its digits is 3456, while the sum is 32.

The square root of 21146918 is about 4598.5778236320. The cubic root of 21146918 is about 276.5343129135.

The spelling of 21146918 in words is "twenty-one million, one hundred forty-six thousand, nine hundred eighteen".