19771387947 has 6 divisors (see below), whose sum is σ = 28558671492. Its totient is φ = 13180925292.

The previous prime is 19771387927. The next prime is 19771387997. The reversal of 19771387947 is 74978317791.

It is not a de Polignac number, because 19771387947 - 2²³ = 19762999339 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19771387927) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1098410433 + ... + 1098410450.

It is an arithmetic number, because the mean of its divisors is an integer number (4759778582).

Almost surely, 2^19771387947 is an apocalyptic number.

19771387947 is a deficient number, since it is larger than the sum of its proper divisors (8787283545).

19771387947 is a wasteful number, since it uses less digits than its factorization.

19771387947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2196820889 (or 2196820886 counting only the distinct ones).

The product of its digits is 18670176, while the sum is 63.

The spelling of 19771387947 in words is "nineteen billion, seven hundred seventy-one million, three hundred eighty-seven thousand, nine hundred forty-seven".