1999999870 has 16 divisors (see below), whose sum is σ = 3927272688. Its totient is φ = 727272640.

The previous prime is 1999999861. The next prime is 1999999871. The reversal of 1999999870 is 789999991.

It is a self number, because there is not a number n which added to its sum of digits gives 1999999870.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1999999871) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9090799 + ... + 9091018.

It is an arithmetic number, because the mean of its divisors is an integer number (245454543).

Almost surely, 2^1999999870 is an apocalyptic number.

1999999870 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1999999870 is a deficient number, since it is larger than the sum of its proper divisors (1927272818).

1999999870 is a wasteful number, since it uses less digits than its factorization.

1999999870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18181835.

The product of its (nonzero) digits is 29760696, while the sum is 70.

The square root of 1999999870 is about 44721.3580965516. The cubic root of 1999999870 is about 1259.9210225966.

The spelling of 1999999870 in words is "one billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred seventy".