21023726 has 4 divisors (see below), whose sum is σ = 31535592. Its totient is φ = 10511862.

The previous prime is 21023701. The next prime is 21023731. The reversal of 21023726 is 62732012.

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

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5255930 + ... + 5255933.

It is an arithmetic number, because the mean of its divisors is an integer number (7883898).

Almost surely, 2^21023726 is an apocalyptic number.

21023726 is a deficient number, since it is larger than the sum of its proper divisors (10511866).

21023726 is a wasteful number, since it uses less digits than its factorization.

21023726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10511865.

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 21023726 is about 4585.1636830107. The cubic root of 21023726 is about 275.9962804932.

Adding to 21023726 its reverse (62732012), we get a palindrome (83755738).

The spelling of 21023726 in words is "twenty-one million, twenty-three thousand, seven hundred twenty-six".