1778961640 has 32 divisors (see below), whose sum is σ = 4213332000. Its totient is φ = 674132544.

The previous prime is 1778961619. The next prime is 1778961647. The reversal of 1778961640 is 461698771.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (1778961647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1169610 + ... + 1171129.

It is an arithmetic number, because the mean of its divisors is an integer number (131666625).

Almost surely, 2^1778961640 is an apocalyptic number.

1778961640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1778961640 is an abundant number, since it is smaller than the sum of its proper divisors (2434370360).

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

1778961640 is a wasteful number, since it uses less digits than its factorization.

1778961640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2340769 (or 2340765 counting only the distinct ones).

The product of its (nonzero) digits is 508032, while the sum is 49.

The square root of 1778961640 is about 42177.7386781226. The cubic root of 1778961640 is about 1211.6825714403.

The spelling of 1778961640 in words is "one billion, seven hundred seventy-eight million, nine hundred sixty-one thousand, six hundred forty".