1999549971 has 12 divisors (see below), whose sum is σ = 2987833680. Its totient is φ = 1287066480.

The previous prime is 1999549963. The next prime is 1999549997. The reversal of 1999549971 is 1799459991.

1999549971 is a `hidden beast` number, since 19 + 9 + 9 + 549 + 9 + 71 = 666.

It is not a de Polignac number, because 1999549971 - 2³ = 1999549963 is a prime.

It is a super-2 number, since 2×1999549971² = 7996400173052201682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1999549899 and 1999549908.

It is not an unprimeable number, because it can be changed into a prime (1999549771) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3830295 + ... + 3830816.

It is an arithmetic number, because the mean of its divisors is an integer number (248986140).

Almost surely, 2^1999549971 is an apocalyptic number.

1999549971 is a deficient number, since it is larger than the sum of its proper divisors (988283709).

1999549971 is a wasteful number, since it uses less digits than its factorization.

1999549971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7661146 (or 7661143 counting only the distinct ones).

The product of its digits is 8266860, while the sum is 63.

The square root of 1999549971 is about 44716.3277897459. The cubic root of 1999549971 is about 1259.8265426377.

The spelling of 1999549971 in words is "one billion, nine hundred ninety-nine million, five hundred forty-nine thousand, nine hundred seventy-one".