21042120455 has 8 divisors (see below), whose sum is σ = 25356196800. Its totient is φ = 16763261536.

The previous prime is 21042120443. The next prime is 21042120487. The reversal of 21042120455 is 55402124012.

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 21042120455 - 2⁸ = 21042120199 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8803040 + ... + 8805429.

It is an arithmetic number, because the mean of its divisors is an integer number (3169524600).

Almost surely, 2^21042120455 is an apocalyptic number.

21042120455 is a deficient number, since it is larger than the sum of its proper divisors (4314076345).

21042120455 is a wasteful number, since it uses less digits than its factorization.

21042120455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17608713.

The product of its (nonzero) digits is 3200, while the sum is 26.

Adding to 21042120455 its reverse (55402124012), we get a palindrome (76444244467).

The spelling of 21042120455 in words is "twenty-one billion, forty-two million, one hundred twenty thousand, four hundred fifty-five".