1999971 has 10 divisors (see below), whose sum is σ = 2987732. Its totient is φ = 1333260.

The previous prime is 1999969. The next prime is 1999979. The reversal of 1999971 is 1799991.

It is not a de Polignac number, because 1999971 - 2¹ = 1999969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1999979) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 12265 + ... + 12426.

2^1999971 is an apocalyptic number.

1999971 is a deficient number, since it is larger than the sum of its proper divisors (987761).

1999971 is an equidigital number, since it uses as much as digits as its factorization.

1999971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24703 (or 24694 counting only the distinct ones).

The product of its digits is 45927, while the sum is 45.

The square root of 1999971 is about 1414.2033092876. The cubic root of 1999971 is about 125.9914960247.

The spelling of 1999971 in words is "one million, nine hundred ninety-nine thousand, nine hundred seventy-one".