1778400243 has 24 divisors (see below), whose sum is σ = 2766020400. Its totient is φ = 1096940544.

The previous prime is 1778400203. The next prime is 1778400251. The reversal of 1778400243 is 3420048771.

It is a happy number.

1778400243 is a `hidden beast` number, since 1 + 7 + 7 + 8 + 400 + 243 = 666.

It is not a de Polignac number, because 1778400243 - 2¹⁶ = 1778334707 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1778400198 and 1778400207.

It is not an unprimeable number, because it can be changed into a prime (1778400203) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 89478 + ... + 107531.

It is an arithmetic number, because the mean of its divisors is an integer number (115250850).

Almost surely, 2^1778400243 is an apocalyptic number.

1778400243 is a deficient number, since it is larger than the sum of its proper divisors (987620157).

1778400243 is a wasteful number, since it uses less digits than its factorization.

1778400243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197091 (or 197088 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 36.

The square root of 1778400243 is about 42171.0830190547. The cubic root of 1778400243 is about 1211.5550988531. Note that the first 3 decimals are identical.

The spelling of 1778400243 in words is "one billion, seven hundred seventy-eight million, four hundred thousand, two hundred forty-three".