21020020001688 has 64 divisors (see below), whose sum is σ = 52683242785920. Its totient is φ = 6988928486400.

The previous prime is 21020020001671. The next prime is 21020020001689. The reversal of 21020020001688 is 88610002002012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020020001689) 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, 23326143 + ... + 24210513.

It is an arithmetic number, because the mean of its divisors is an integer number (823175668530).

Almost surely, 2^{21020020001688} is an apocalyptic number.

It is an amenable number.

21020020001688 is an abundant number, since it is smaller than the sum of its proper divisors (31663222784232).

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

21020020001688 is a wasteful number, since it uses less digits than its factorization.

21020020001688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 886888 (or 886884 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 30.

The spelling of 21020020001688 in words is "twenty-one trillion, twenty billion, twenty million, one thousand, six hundred eighty-eight".