21121418 has 8 divisors (see below), whose sum is σ = 31705248. Its totient is φ = 10553004.

The previous prime is 21121417. The next prime is 21121453. The reversal of 21121418 is 81412112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21121418² = 892228596661448, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21121418.

It is not an unprimeable number, because it can be changed into a prime (21121411) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 605 + ... + 6527.

It is an arithmetic number, because the mean of its divisors is an integer number (3963156).

Almost surely, 2^21121418 is an apocalyptic number.

21121418 is a deficient number, since it is larger than the sum of its proper divisors (10583830).

21121418 is a wasteful number, since it uses less digits than its factorization.

21121418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7708.

The product of its digits is 128, while the sum is 20.

The square root of 21121418 is about 4595.8043909636. The cubic root of 21121418 is about 276.4231152868.

The spelling of 21121418 in words is "twenty-one million, one hundred twenty-one thousand, four hundred eighteen".