21523126 has 4 divisors (see below), whose sum is σ = 32284692. Its totient is φ = 10761562.

The previous prime is 21523093. The next prime is 21523171. The reversal of 21523126 is 62132512.

It is a semiprime because it is the product of two primes.

It is a super-3 number, since 3×21523126³ (a number of 23 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21523097 and 21523106.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5380780 + ... + 5380783.

It is an arithmetic number, because the mean of its divisors is an integer number (8071173).

Almost surely, 2^21523126 is an apocalyptic number.

21523126 is a deficient number, since it is larger than the sum of its proper divisors (10761566).

21523126 is a wasteful number, since it uses less digits than its factorization.

21523126 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10761565.

The product of its digits is 720, while the sum is 22.

The square root of 21523126 is about 4639.3023182371. The cubic root of 21523126 is about 278.1645507193.

Adding to 21523126 its reverse (62132512), we get a palindrome (83655638).

The spelling of 21523126 in words is "twenty-one million, five hundred twenty-three thousand, one hundred twenty-six".