21130402340 has 12 divisors (see below), whose sum is σ = 44373844956. Its totient is φ = 8452160928.

The previous prime is 21130402333. The next prime is 21130402387. The reversal of 21130402340 is 4320403112.

It can be written as a sum of positive squares in 2 ways, for example, as 13835875876 + 7294526464 = 117626^2 + 85408^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1056520117 = 21130402340 / (2 + 1 + 1 + 3 + 0 + 4 + 0 + 2 + 3 + 4 + 0).

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 528260039 + ... + 528260078.

It is an arithmetic number, because the mean of its divisors is an integer number (3697820413).

Almost surely, 2^21130402340 is an apocalyptic number.

21130402340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21130402340 is an abundant number, since it is smaller than the sum of its proper divisors (23243442616).

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

21130402340 is a wasteful number, since it uses less digits than its factorization.

21130402340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1056520126 (or 1056520124 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 21130402340 its reverse (4320403112), we get a palindrome (25450805452).

The spelling of 21130402340 in words is "twenty-one billion, one hundred thirty million, four hundred two thousand, three hundred forty".