21154911 has 8 divisors (see below), whose sum is σ = 28229040. Its totient is φ = 14092032.

The previous prime is 21154909. The next prime is 21154921. The reversal of 21154911 is 11945112.

It is a happy number.

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

It is not a de Polignac number, because 21154911 - 2¹ = 21154909 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21154921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3801 + ... + 7533.

It is an arithmetic number, because the mean of its divisors is an integer number (3528630).

Almost surely, 2^21154911 is an apocalyptic number.

21154911 is a deficient number, since it is larger than the sum of its proper divisors (7074129).

21154911 is a wasteful number, since it uses less digits than its factorization.

21154911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5625.

The product of its digits is 360, while the sum is 24.

The square root of 21154911 is about 4599.4468145637. The cubic root of 21154911 is about 276.5691495161.

The spelling of 21154911 in words is "twenty-one million, one hundred fifty-four thousand, nine hundred eleven".