21642461155 has 16 divisors (see below), whose sum is σ = 29721288960. Its totient is φ = 14820445152.

The previous prime is 21642461111. The next prime is 21642461227. The reversal of 21642461155 is 55116424612.

It is a cyclic number.

It is not a de Polignac number, because 21642461155 - 2¹¹ = 21642459107 is a prime.

It is a super-2 number, since 2×21642461155² (a number of 21 digits) contains 22 as substring.

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 15 ways as a sum of consecutive naturals, for example, 392509 + ... + 444238.

It is an arithmetic number, because the mean of its divisors is an integer number (1857580560).

Almost surely, 2^21642461155 is an apocalyptic number.

21642461155 is a deficient number, since it is larger than the sum of its proper divisors (8078827805).

21642461155 is an equidigital number, since it uses as much as digits as its factorization.

21642461155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 837498.

The product of its digits is 57600, while the sum is 37.

Adding to 21642461155 its reverse (55116424612), we get a palindrome (76758885767).

The spelling of 21642461155 in words is "twenty-one billion, six hundred forty-two million, four hundred sixty-one thousand, one hundred fifty-five".