212115661660 has 96 divisors (see below), whose sum is σ = 511190934912. Its totient is φ = 72423936000.

The previous prime is 212115661651. The next prime is 212115661663. The reversal of 212115661660 is 66166511212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212115661663) 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, 70680160 + ... + 70683160.

It is an arithmetic number, because the mean of its divisors is an integer number (5324905572).

Almost surely, 2^212115661660 is an apocalyptic number.

212115661660 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 212115661660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (255595467456).

212115661660 is an abundant number, since it is smaller than the sum of its proper divisors (299075273252).

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

212115661660 is a wasteful number, since it uses less digits than its factorization.

212115661660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4943 (or 4941 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 37.

The spelling of 212115661660 in words is "two hundred twelve billion, one hundred fifteen million, six hundred sixty-one thousand, six hundred sixty".