21707977212 has 144 divisors (see below), whose sum is σ = 59957100000. Its totient is φ = 6790791168.

The previous prime is 21707977183. The next prime is 21707977237. The reversal of 21707977212 is 21277970712.

It is a happy number.

It is a super-2 number, since 2×21707977212² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14013414 + ... + 14014962.

It is an arithmetic number, because the mean of its divisors is an integer number (416368750).

Almost surely, 2^21707977212 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 21707977212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29978550000).

21707977212 is an abundant number, since it is smaller than the sum of its proper divisors (38249122788).

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

21707977212 is a wasteful number, since it uses less digits than its factorization.

21707977212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2045 (or 2020 counting only the distinct ones).

The product of its (nonzero) digits is 172872, while the sum is 45.

The spelling of 21707977212 in words is "twenty-one billion, seven hundred seven million, nine hundred seventy-seven thousand, two hundred twelve".