21042122555 has 64 divisors (see below), whose sum is σ = 28146216960. Its totient is φ = 15033600000.

The previous prime is 21042122537. The next prime is 21042122561. The reversal of 21042122555 is 55522124012.

It is a happy number.

It is not a de Polignac number, because 21042122555 - 2³² = 16747155259 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 28018430 + ... + 28019180.

It is an arithmetic number, because the mean of its divisors is an integer number (439784640).

Almost surely, 2^21042122555 is an apocalyptic number.

21042122555 is a deficient number, since it is larger than the sum of its proper divisors (7104094405).

21042122555 is a wasteful number, since it uses less digits than its factorization.

21042122555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1020.

The product of its (nonzero) digits is 8000, while the sum is 29.

Adding to 21042122555 its reverse (55522124012), we get a palindrome (76564246567).

The spelling of 21042122555 in words is "twenty-one billion, forty-two million, one hundred twenty-two thousand, five hundred fifty-five".