21516235135207 has 8 divisors (see below), whose sum is σ = 21555457558560. Its totient is φ = 21477017654400.

The previous prime is 21516235135177. The next prime is 21516235135229. The reversal of 21516235135207 is 70253153261512.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21516235135207 - 2¹⁹ = 21516234610919 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21516235135267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7535518 + ... + 9990820.

It is an arithmetic number, because the mean of its divisors is an integer number (2694432194820).

Almost surely, 2^{21516235135207} is an apocalyptic number.

21516235135207 is a deficient number, since it is larger than the sum of its proper divisors (39222423353).

21516235135207 is a wasteful number, since it uses less digits than its factorization.

21516235135207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2471273.

The product of its (nonzero) digits is 378000, while the sum is 43.

Adding to 21516235135207 its reverse (70253153261512), we get a palindrome (91769388396719).

The spelling of 21516235135207 in words is "twenty-one trillion, five hundred sixteen billion, two hundred thirty-five million, one hundred thirty-five thousand, two hundred seven".