21135946 has 8 divisors (see below), whose sum is σ = 34142724. Its totient is φ = 9755040.

The previous prime is 21135911. The next prime is 21135971. The reversal of 21135946 is 64953112.

It can be written as a sum of positive squares in 2 ways, for example, as 17313921 + 3822025 = 4161^2 + 1955^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 406435 + ... + 406486.

Almost surely, 2^21135946 is an apocalyptic number.

21135946 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21135946 is a deficient number, since it is larger than the sum of its proper divisors (13006778).

21135946 is a wasteful number, since it uses less digits than its factorization.

21135946 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 812936.

The product of its digits is 6480, while the sum is 31.

The square root of 21135946 is about 4597.3846913218. The cubic root of 21135946 is about 276.4864783720.

The spelling of 21135946 in words is "twenty-one million, one hundred thirty-five thousand, nine hundred forty-six".