21144523 has 8 divisors (see below), whose sum is σ = 21577808. Its totient is φ = 20715264.

The previous prime is 21144469. The next prime is 21144547. The reversal of 21144523 is 32544112.

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

It is a cyclic number.

It is not a de Polignac number, because 21144523 - 2¹⁷ = 21013451 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21144494 and 21144503.

It is not an unprimeable number, because it can be changed into a prime (21144553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11011 + ... + 12787.

It is an arithmetic number, because the mean of its divisors is an integer number (2697226).

Almost surely, 2^21144523 is an apocalyptic number.

21144523 is a deficient number, since it is larger than the sum of its proper divisors (433285).

21144523 is a wasteful number, since it uses less digits than its factorization.

21144523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2013.

The product of its digits is 960, while the sum is 22.

The square root of 21144523 is about 4598.3174096619. The cubic root of 21144523 is about 276.5238728629.

Adding to 21144523 its reverse (32544112), we get a palindrome (53688635).

The spelling of 21144523 in words is "twenty-one million, one hundred forty-four thousand, five hundred twenty-three".