21423055555 has 16 divisors (see below), whose sum is σ = 28151380224. Its totient is φ = 15521152480.

The previous prime is 21423055519. The next prime is 21423055573. The reversal of 21423055555 is 55555032412.

It is a de Polignac number, because none of the positive numbers 2^k-21423055555 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 726049 + ... + 754978.

It is an arithmetic number, because the mean of its divisors is an integer number (1759461264).

Almost surely, 2^21423055555 is an apocalyptic number.

21423055555 is a deficient number, since it is larger than the sum of its proper divisors (6728324669).

21423055555 is a wasteful number, since it uses less digits than its factorization.

21423055555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1481306.

The product of its (nonzero) digits is 150000, while the sum is 37.

Adding to 21423055555 its reverse (55555032412), we get a palindrome (76978087967).

The spelling of 21423055555 in words is "twenty-one billion, four hundred twenty-three million, fifty-five thousand, five hundred fifty-five".