21155130340 has 48 divisors (see below), whose sum is σ = 45075905280. Its totient is φ = 8338636800.

The previous prime is 21155130307. The next prime is 21155130343. The reversal of 21155130340 is 4303155112.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21155130343) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 813540 + ... + 839140.

It is an arithmetic number, because the mean of its divisors is an integer number (939081360).

Almost surely, 2^21155130340 is an apocalyptic number.

21155130340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21155130340 is an abundant number, since it is smaller than the sum of its proper divisors (23920774940).

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

21155130340 is a wasteful number, since it uses less digits than its factorization.

21155130340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26212 (or 26210 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 25.

Adding to 21155130340 its reverse (4303155112), we get a palindrome (25458285452).

The spelling of 21155130340 in words is "twenty-one billion, one hundred fifty-five million, one hundred thirty thousand, three hundred forty".