21118477 has 4 divisors (see below), whose sum is σ = 21224800. Its totient is φ = 21012156.

The previous prime is 21118441. The next prime is 21118501. The reversal of 21118477 is 77481112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21118477 - 2¹⁵ = 21085709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21118277) 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 in 3 ways as a sum of consecutive naturals, for example, 52863 + ... + 53260.

It is an arithmetic number, because the mean of its divisors is an integer number (5306200).

Almost surely, 2^21118477 is an apocalyptic number.

It is an amenable number.

21118477 is a deficient number, since it is larger than the sum of its proper divisors (106323).

21118477 is a wasteful number, since it uses less digits than its factorization.

21118477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106322.

The product of its digits is 3136, while the sum is 31.

The square root of 21118477 is about 4595.4844140743. The cubic root of 21118477 is about 276.4102847386.

Adding to 21118477 its reverse (77481112), we get a palindrome (98599589).

The spelling of 21118477 in words is "twenty-one million, one hundred eighteen thousand, four hundred seventy-seven".