21955118 has 4 divisors (see below), whose sum is σ = 32932680. Its totient is φ = 10977558.

The previous prime is 21955093. The next prime is 21955121. The reversal of 21955118 is 81155912.

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

It is a congruent number.

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, 5488778 + ... + 5488781.

It is an arithmetic number, because the mean of its divisors is an integer number (8233170).

Almost surely, 2^21955118 is an apocalyptic number.

21955118 is a deficient number, since it is larger than the sum of its proper divisors (10977562).

21955118 is a wasteful number, since it uses less digits than its factorization.

21955118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10977561.

The product of its digits is 3600, while the sum is 32.

The square root of 21955118 is about 4685.6288798837. The cubic root of 21955118 is about 280.0132561751.

The spelling of 21955118 in words is "twenty-one million, nine hundred fifty-five thousand, one hundred eighteen".