1205781642 has 96 divisors (see below), whose sum is σ = 2931941376. Its totient is φ = 355622400.

The previous prime is 1205781617. The next prime is 1205781671. The reversal of 1205781642 is 2461875021.

1205781642 is a `hidden beast` number, since 1 + 2 + 0 + 5 + 7 + 8 + 1 + 642 = 666.

1205781642 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 1205781597 and 1205781606.

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, 818967 + ... + 820437.

It is an arithmetic number, because the mean of its divisors is an integer number (30541056).

Almost surely, 2^1205781642 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1205781642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1465970688).

1205781642 is an abundant number, since it is smaller than the sum of its proper divisors (1726159734).

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

1205781642 is a wasteful number, since it uses less digits than its factorization.

1205781642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1636 (or 1633 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 1205781642 is about 34724.3666896892. The cubic root of 1205781642 is about 1064.3624776684.

The spelling of 1205781642 in words is "one billion, two hundred five million, seven hundred eighty-one thousand, six hundred forty-two".