21251123 has 2 divisors, whose sum is σ = 21251124. Its totient is φ = 21251122.

The previous prime is 21251117. The next prime is 21251129. The reversal of 21251123 is 32115212.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (21251117) and next prime (21251129).

It is a cyclic number.

It is not a de Polignac number, because 21251123 - 2¹² = 21247027 is a prime.

It is a super-2 number, since 2×21251123² = 903220457522258, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21251129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10625561 + 10625562.

It is an arithmetic number, because the mean of its divisors is an integer number (10625562).

Almost surely, 2^21251123 is an apocalyptic number.

21251123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21251123 is an equidigital number, since it uses as much as digits as its factorization.

21251123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120, while the sum is 17.

The square root of 21251123 is about 4609.8940334893. The cubic root of 21251123 is about 276.9877919959.

Adding to 21251123 its reverse (32115212), we get a palindrome (53366335).

The spelling of 21251123 in words is "twenty-one million, two hundred fifty-one thousand, one hundred twenty-three".