21644954 has 4 divisors (see below), whose sum is σ = 32467434. Its totient is φ = 10822476.

The previous prime is 21644947. The next prime is 21644969. The reversal of 21644954 is 45944612.

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., 13653025 + 7991929 = 3695^2 + 2827^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5411237 + ... + 5411240.

Almost surely, 2^21644954 is an apocalyptic number.

21644954 is a deficient number, since it is larger than the sum of its proper divisors (10822480).

21644954 is a wasteful number, since it uses less digits than its factorization.

21644954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10822479.

The product of its digits is 34560, while the sum is 35.

The square root of 21644954 is about 4652.4137821135. The cubic root of 21644954 is about 278.6883979782.

The spelling of 21644954 in words is "twenty-one million, six hundred forty-four thousand, nine hundred fifty-four".