21042726 has 16 divisors (see below), whose sum is σ = 42276864. Its totient is φ = 6982344.

The previous prime is 21042689. The next prime is 21042731. The reversal of 21042726 is 62724012.

It is a super-2 number, since 2×21042726² = 885592635022152, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21042696 and 21042705.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6526 + ... + 9201.

It is an arithmetic number, because the mean of its divisors is an integer number (2642304).

Almost surely, 2^21042726 is an apocalyptic number.

21042726 is an abundant number, since it is smaller than the sum of its proper divisors (21234138).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21042726 is a wasteful number, since it uses less digits than its factorization.

21042726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15955.

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 21042726 is about 4587.2351149685. The cubic root of 21042726 is about 276.0793984968.

Adding to 21042726 its reverse (62724012), we get a palindrome (83766738).

The spelling of 21042726 in words is "twenty-one million, forty-two thousand, seven hundred twenty-six".