21266542 has 8 divisors (see below), whose sum is σ = 34799832. Its totient is φ = 9666600.

The previous prime is 21266521. The next prime is 21266551. The reversal of 21266542 is 24566212.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21266542.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 483309 + ... + 483352.

It is an arithmetic number, because the mean of its divisors is an integer number (4349979).

Almost surely, 2^21266542 is an apocalyptic number.

21266542 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21266542 is a deficient number, since it is larger than the sum of its proper divisors (13533290).

21266542 is a wasteful number, since it uses less digits than its factorization.

21266542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 966674.

The product of its digits is 5760, while the sum is 28.

The square root of 21266542 is about 4611.5661114203. The cubic root of 21266542 is about 277.0547663742.

It can be divided in two parts, 2126 and 6542, that added together give a palindrome (8668).

The spelling of 21266542 in words is "twenty-one million, two hundred sixty-six thousand, five hundred forty-two".