1781801406 has 144 divisors (see below), whose sum is σ = 5014234368. Its totient is φ = 451936800.

The previous prime is 1781801389. The next prime is 1781801407. The reversal of 1781801406 is 6041081871.

1781801406 is a `hidden beast` number, since 1 + 78 + 180 + 1 + 406 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1781801407) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 415051 + ... + 419321.

It is an arithmetic number, because the mean of its divisors is an integer number (34821072).

Almost surely, 2^1781801406 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1781801406, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2507117184).

1781801406 is an abundant number, since it is smaller than the sum of its proper divisors (3232432962).

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

1781801406 is a wasteful number, since it uses less digits than its factorization.

1781801406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4347 (or 4337 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 36.

The square root of 1781801406 is about 42211.3895293675. The cubic root of 1781801406 is about 1212.3269671386.

The spelling of 1781801406 in words is "one billion, seven hundred eighty-one million, eight hundred one thousand, four hundred six".