21155507234 has 32 divisors (see below), whose sum is σ = 34213921776. Its totient is φ = 9774213120.

The previous prime is 21155507201. The next prime is 21155507239. The reversal of 21155507234 is 43270555112.

It can be written as a sum of positive squares in 8 ways, for example, as 1345789225 + 19809718009 = 36685^2 + 140747^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21155507194 and 21155507203.

It is not an unprimeable number, because it can be changed into a prime (21155507239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1146062 + ... + 1164374.

Almost surely, 2^21155507234 is an apocalyptic number.

21155507234 is a deficient number, since it is larger than the sum of its proper divisors (13058414542).

21155507234 is a wasteful number, since it uses less digits than its factorization.

21155507234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18950.

The product of its (nonzero) digits is 42000, while the sum is 35.

The spelling of 21155507234 in words is "twenty-one billion, one hundred fifty-five million, five hundred seven thousand, two hundred thirty-four".