1999685051 has 36 divisors (see below), whose sum is σ = 2542255632. Its totient is φ = 1559035296.

The previous prime is 1999685047. The next prime is 1999685057. The reversal of 1999685051 is 1505869991.

It is not a de Polignac number, because 1999685051 - 2² = 1999685047 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1999684984 and 1999685002.

It is not an unprimeable number, because it can be changed into a prime (1999685057) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3975266 + ... + 3975768.

It is an arithmetic number, because the mean of its divisors is an integer number (70618212).

Almost surely, 2^1999685051 is an apocalyptic number.

1999685051 is a deficient number, since it is larger than the sum of its proper divisors (542570581).

1999685051 is an equidigital number, since it uses as much as digits as its factorization.

1999685051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 688 (or 602 counting only the distinct ones).

The product of its (nonzero) digits is 874800, while the sum is 53.

The square root of 1999685051 is about 44717.8381744914. The cubic root of 1999685051 is about 1259.8549112772.

The spelling of 1999685051 in words is "one billion, nine hundred ninety-nine million, six hundred eighty-five thousand, fifty-one".