21251442535 has 8 divisors (see below), whose sum is σ = 27001832976. Its totient is φ = 16001086080.

The previous prime is 21251442481. The next prime is 21251442539. The reversal of 21251442535 is 53524415212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21251442535 - 2¹³ = 21251434343 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21251442535.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21251442539) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 125008401 + ... + 125008570.

It is an arithmetic number, because the mean of its divisors is an integer number (3375229122).

Almost surely, 2^21251442535 is an apocalyptic number.

21251442535 is a deficient number, since it is larger than the sum of its proper divisors (5750390441).

21251442535 is a wasteful number, since it uses less digits than its factorization.

21251442535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250016993.

The product of its digits is 48000, while the sum is 34.

Adding to 21251442535 its reverse (53524415212), we get a palindrome (74775857747).

The spelling of 21251442535 in words is "twenty-one billion, two hundred fifty-one million, four hundred forty-two thousand, five hundred thirty-five".