21025118 has 4 divisors (see below), whose sum is σ = 31537680. Its totient is φ = 10512558.

The previous prime is 21025117. The next prime is 21025127. The reversal of 21025118 is 81152012.

It is a happy number.

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

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21025118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21025117) by changing a digit.

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, 5256278 + ... + 5256281.

It is an arithmetic number, because the mean of its divisors is an integer number (7884420).

Almost surely, 2^21025118 is an apocalyptic number.

21025118 is a deficient number, since it is larger than the sum of its proper divisors (10512562).

21025118 is a wasteful number, since it uses less digits than its factorization.

21025118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10512561.

The product of its (nonzero) digits is 160, while the sum is 20.

The square root of 21025118 is about 4585.3154744249. The cubic root of 21025118 is about 276.0023716802.

The spelling of 21025118 in words is "twenty-one million, twenty-five thousand, one hundred eighteen".