21206716080 has 160 divisors (see below), whose sum is σ = 72700346880. Its totient is φ = 5070551040.

The previous prime is 21206716073. The next prime is 21206716087. The reversal of 21206716080 is 8061760212.

It is an interprime number because it is at equal distance from previous prime (21206716073) and next prime (21206716087).

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21206716087) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 137701 + ... + 247739.

It is an arithmetic number, because the mean of its divisors is an integer number (454377168).

Almost surely, 2^21206716080 is an apocalyptic number.

21206716080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21206716080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36350173440).

21206716080 is an abundant number, since it is smaller than the sum of its proper divisors (51493630800).

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

21206716080 is a wasteful number, since it uses less digits than its factorization.

21206716080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110139 (or 110133 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 33.

The spelling of 21206716080 in words is "twenty-one billion, two hundred six million, seven hundred sixteen thousand, eighty".