21053435208 has 64 divisors (see below), whose sum is σ = 56795437440. Its totient is φ = 6465053184.

The previous prime is 21053435191. The next prime is 21053435281. The reversal of 21053435208 is 80253435012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89860 + ... + 224012.

It is an arithmetic number, because the mean of its divisors is an integer number (887428710).

Almost surely, 2^21053435208 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21053435208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28397718720).

21053435208 is an abundant number, since it is smaller than the sum of its proper divisors (35742002232).

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

21053435208 is a wasteful number, since it uses less digits than its factorization.

21053435208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134678 (or 134674 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 33.

The spelling of 21053435208 in words is "twenty-one billion, fifty-three million, four hundred thirty-five thousand, two hundred eight".