1947138819 has 4 divisors (see below), whose sum is σ = 2596185096. Its totient is φ = 1298092544.

The previous prime is 1947138811. The next prime is 1947138839. The reversal of 1947138819 is 9188317491.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1947138819 - 2³ = 1947138811 is a prime.

It is a super-2 number, since 2×1947138819² = 7582699160913429522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1947138811) 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, 324523134 + ... + 324523139.

It is an arithmetic number, because the mean of its divisors is an integer number (649046274).

Almost surely, 2^1947138819 is an apocalyptic number.

1947138819 is a deficient number, since it is larger than the sum of its proper divisors (649046277).

1947138819 is an equidigital number, since it uses as much as digits as its factorization.

1947138819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 649046276.

The product of its digits is 435456, while the sum is 51.

The square root of 1947138819 is about 44126.3959439245. The cubic root of 1947138819 is about 1248.7216411379.

The spelling of 1947138819 in words is "one billion, nine hundred forty-seven million, one hundred thirty-eight thousand, eight hundred nineteen".