21555342015 has 64 divisors (see below), whose sum is σ = 38479795200. Its totient is φ = 10239657984.

The previous prime is 21555342001. The next prime is 21555342019. The reversal of 21555342015 is 51024355512.

It is not a de Polignac number, because 21555342015 - 2²⁸ = 21286906559 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21555342019) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 6388869 + ... + 6392241.

It is an arithmetic number, because the mean of its divisors is an integer number (601246800).

Almost surely, 2^21555342015 is an apocalyptic number.

21555342015 is a deficient number, since it is larger than the sum of its proper divisors (16924453185).

21555342015 is a wasteful number, since it uses less digits than its factorization.

21555342015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4736.

The product of its (nonzero) digits is 30000, while the sum is 33.

Adding to 21555342015 its reverse (51024355512), we get a palindrome (72579697527).

The spelling of 21555342015 in words is "twenty-one billion, five hundred fifty-five million, three hundred forty-two thousand, fifteen".