21783532155 has 64 divisors (see below), whose sum is σ = 43785916416. Its totient is φ = 8983728000.

The previous prime is 21783532103. The next prime is 21783532157. The reversal of 21783532155 is 55123538712.

It is not a de Polignac number, because 21783532155 - 2⁸ = 21783531899 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21783532157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 79320 + ... + 223290.

It is an arithmetic number, because the mean of its divisors is an integer number (684154944).

Almost surely, 2^21783532155 is an apocalyptic number.

21783532155 is an abundant number, since it is smaller than the sum of its proper divisors (22002384261).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21783532155 is a wasteful number, since it uses less digits than its factorization.

21783532155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144128.

The product of its digits is 252000, while the sum is 42.

The spelling of 21783532155 in words is "twenty-one billion, seven hundred eighty-three million, five hundred thirty-two thousand, one hundred fifty-five".