21016520020 has 24 divisors (see below), whose sum is σ = 46053592704. Its totient is φ = 8041103136.

The previous prime is 21016519969. The next prime is 21016520051. The reversal of 21016520020 is 2002561012.

It is a super-2 number, since 2×21016520020² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21016520020.

It is a congruent number.

It is an unprimeable number.

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, 22843584 + ... + 22844503.

It is an arithmetic number, because the mean of its divisors is an integer number (1918899696).

Almost surely, 2^21016520020 is an apocalyptic number.

21016520020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21016520020 is an abundant number, since it is smaller than the sum of its proper divisors (25037072684).

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

21016520020 is a wasteful number, since it uses less digits than its factorization.

21016520020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45688119 (or 45688117 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The spelling of 21016520020 in words is "twenty-one billion, sixteen million, five hundred twenty thousand, twenty".