21121535204 has 24 divisors (see below), whose sum is σ = 46083350208. Its totient is φ = 8229169440.

The previous prime is 21121535203. The next prime is 21121535209. The reversal of 21121535204 is 40253512112.

It is a super-2 number, since 2×21121535204² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121535203) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 34287899 + ... + 34288514.

It is an arithmetic number, because the mean of its divisors is an integer number (1920139592).

Almost surely, 2^21121535204 is an apocalyptic number.

It is an amenable number.

21121535204 is an abundant number, since it is smaller than the sum of its proper divisors (24961815004).

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

21121535204 is a wasteful number, since it uses less digits than its factorization.

21121535204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68576435 (or 68576433 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 26.

The spelling of 21121535204 in words is "twenty-one billion, one hundred twenty-one million, five hundred thirty-five thousand, two hundred four".