21142102340 has 12 divisors (see below), whose sum is σ = 44398414956. Its totient is φ = 8456840928.

The previous prime is 21142102243. The next prime is 21142102349. The reversal of 21142102340 is 4320124112.

It can be written as a sum of positive squares in 2 ways, for example, as 15611502916 + 5530599424 = 124946^2 + 74368^2 .

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: 1057105117 = 21142102340 / (2 + 1 + 1 + 4 + 2 + 1 + 0 + 2 + 3 + 4 + 0).

It is not an unprimeable number, because it can be changed into a prime (21142102349) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 528552539 + ... + 528552578.

It is an arithmetic number, because the mean of its divisors is an integer number (3699867913).

Almost surely, 2^21142102340 is an apocalyptic number.

21142102340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21142102340 is an abundant number, since it is smaller than the sum of its proper divisors (23256312616).

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

21142102340 is a wasteful number, since it uses less digits than its factorization.

21142102340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1057105126 (or 1057105124 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 21142102340 its reverse (4320124112), we get a palindrome (25462226452).

The spelling of 21142102340 in words is "twenty-one billion, one hundred forty-two million, one hundred two thousand, three hundred forty".