21151123 has 16 divisors (see below), whose sum is σ = 25696000. Its totient is φ = 17006112.

The previous prime is 21151069. The next prime is 21151147. The reversal of 21151123 is 32115112.

It is a 12-Lehmer number, since φ(21151123) divides (21151123-1)¹².

It is a cyclic number.

It is not a de Polignac number, because 21151123 - 2¹³ = 21142931 is a prime.

It is a super-2 number, since 2×21151123² = 894740008322258, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21151097 and 21151106.

It is not an unprimeable number, because it can be changed into a prime (21151183) 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 15 ways as a sum of consecutive naturals, for example, 13768 + ... + 15226.

It is an arithmetic number, because the mean of its divisors is an integer number (1606000).

Almost surely, 2^21151123 is an apocalyptic number.

21151123 is a deficient number, since it is larger than the sum of its proper divisors (4544877).

21151123 is a wasteful number, since it uses less digits than its factorization.

21151123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1594.

The product of its digits is 60, while the sum is 16.

The square root of 21151123 is about 4599.0350074771. The cubic root of 21151123 is about 276.5526410330.

Adding to 21151123 its reverse (32115112), we get a palindrome (53266235).

The spelling of 21151123 in words is "twenty-one million, one hundred fifty-one thousand, one hundred twenty-three".