2171780406 has 12 divisors (see below), whose sum is σ = 4705524252. Its totient is φ = 723926796.

The previous prime is 2171780399. The next prime is 2171780437. The reversal of 2171780406 is 6040871712.

2171780406 is a `hidden beast` number, since 2 + 171 + 7 + 80 + 406 = 666.

2171780406 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 60327216 + ... + 60327251.

It is an arithmetic number, because the mean of its divisors is an integer number (392127021).

Almost surely, 2^2171780406 is an apocalyptic number.

2171780406 is an abundant number, since it is smaller than the sum of its proper divisors (2533743846).

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

2171780406 is a wasteful number, since it uses less digits than its factorization.

2171780406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120654475 (or 120654472 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 2171780406 is about 46602.3648112411. The cubic root of 2171780406 is about 1295.0065653628.

The spelling of 2171780406 in words is "two billion, one hundred seventy-one million, seven hundred eighty thousand, four hundred six".