21911738 has 4 divisors (see below), whose sum is σ = 32867610. Its totient is φ = 10955868.

The previous prime is 21911713. The next prime is 21911741. The reversal of 21911738 is 83711912.

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., 13344409 + 8567329 = 3653^2 + 2927^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5477933 + ... + 5477936.

Almost surely, 2^21911738 is an apocalyptic number.

21911738 is a deficient number, since it is larger than the sum of its proper divisors (10955872).

21911738 is a wasteful number, since it uses less digits than its factorization.

21911738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10955871.

The product of its digits is 3024, while the sum is 32.

The square root of 21911738 is about 4680.9975432593. The cubic root of 21911738 is about 279.8287132659.

The spelling of 21911738 in words is "twenty-one million, nine hundred eleven thousand, seven hundred thirty-eight".