21402040055 has 32 divisors (see below), whose sum is σ = 28805122368. Its totient is φ = 15128294400.

The previous prime is 21402040013. The next prime is 21402040067. The reversal of 21402040055 is 55004020412.

It is a happy number.

It is not a de Polignac number, because 21402040055 - 2¹² = 21402035959 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21402040055.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2097065 + ... + 2107245.

It is an arithmetic number, because the mean of its divisors is an integer number (900160074).

Almost surely, 2^21402040055 is an apocalyptic number.

21402040055 is a deficient number, since it is larger than the sum of its proper divisors (7403082313).

21402040055 is a wasteful number, since it uses less digits than its factorization.

21402040055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11267.

The product of its (nonzero) digits is 1600, while the sum is 23.

Adding to 21402040055 its reverse (55004020412), we get a palindrome (76406060467).

The spelling of 21402040055 in words is "twenty-one billion, four hundred two million, forty thousand, fifty-five".