3819778561 has 4 divisors (see below), whose sum is σ = 3823456000. Its totient is φ = 3816101124.

The previous prime is 3819778559. The next prime is 3819778579. The reversal of 3819778561 is 1658779183.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1658779183 = 17489 ⋅94847.

It is a cyclic number.

It is not a de Polignac number, because 3819778561 - 2¹ = 3819778559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3819778541) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1837161 + ... + 1839238.

It is an arithmetic number, because the mean of its divisors is an integer number (955864000).

Almost surely, 2^3819778561 is an apocalyptic number.

It is an amenable number.

3819778561 is a deficient number, since it is larger than the sum of its proper divisors (3677439).

3819778561 is a wasteful number, since it uses less digits than its factorization.

3819778561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3677438.

The product of its digits is 2540160, while the sum is 55.

The square root of 3819778561 is about 61804.3571360466. The cubic root of 3819778561 is about 1563.1934583836.

The spelling of 3819778561 in words is "three billion, eight hundred nineteen million, seven hundred seventy-eight thousand, five hundred sixty-one".