21601161612 has 18 divisors (see below), whose sum is σ = 54602936388. Its totient is φ = 7200387192.

The previous prime is 21601161607. The next prime is 21601161613. The reversal of 21601161612 is 21616110612.

21601161612 is a `hidden beast` number, since 21 + 6 + 0 + 11 + 616 + 12 = 666.

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×21601161612² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21601161613) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 300016098 + ... + 300016169.

It is an arithmetic number, because the mean of its divisors is an integer number (3033496466).

Almost surely, 2^21601161612 is an apocalyptic number.

It is an amenable number.

21601161612 is an abundant number, since it is smaller than the sum of its proper divisors (33001774776).

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

21601161612 is a wasteful number, since it uses less digits than its factorization.

21601161612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 600032277 (or 600032272 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The spelling of 21601161612 in words is "twenty-one billion, six hundred one million, one hundred sixty-one thousand, six hundred twelve".