21121510235 has 16 divisors (see below), whose sum is σ = 29008595712. Its totient is φ = 14462344800.

The previous prime is 21121510219. The next prime is 21121510237. The reversal of 21121510235 is 53201512112.

It is not a de Polignac number, because 21121510235 - 2⁴ = 21121510219 is a prime.

It is a super-2 number, since 2×21121510235² (a number of 21 digits) contains 22 as substring.

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 21121510235.

It is not an unprimeable number, because it can be changed into a prime (21121510237) 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, 412481 + ... + 460850.

It is an arithmetic number, because the mean of its divisors is an integer number (1813037232).

Almost surely, 2^21121510235 is an apocalyptic number.

21121510235 is a deficient number, since it is larger than the sum of its proper divisors (7887085477).

21121510235 is an equidigital number, since it uses as much as digits as its factorization.

21121510235 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 874034.

The product of its (nonzero) digits is 600, while the sum is 23.

The spelling of 21121510235 in words is "twenty-one billion, one hundred twenty-one million, five hundred ten thousand, two hundred thirty-five".