21111946 has 4 divisors (see below), whose sum is σ = 31667922. Its totient is φ = 10555972.

The previous prime is 21111931. The next prime is 21111991. The reversal of 21111946 is 64911112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 12638025 + 8473921 = 3555^2 + 2911^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21111946.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5277985 + ... + 5277988.

Almost surely, 2^21111946 is an apocalyptic number.

21111946 is a deficient number, since it is larger than the sum of its proper divisors (10555976).

21111946 is a wasteful number, since it uses less digits than its factorization.

21111946 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10555975.

The product of its digits is 432, while the sum is 25.

The square root of 21111946 is about 4594.7737702742. The cubic root of 21111946 is about 276.3817880231.

The spelling of 21111946 in words is "twenty-one million, one hundred eleven thousand, nine hundred forty-six".