1999999656 has 48 divisors (see below), whose sum is σ = 5464623060. Its totient is φ = 660764160.

The previous prime is 1999999649. The next prime is 1999999657. The reversal of 1999999656 is 6569999991.

It can be written as a sum of positive squares in 2 ways, for example, as 1456643556 + 543356100 = 38166^2 + 23310^2 .

It is a Harshad number since it is a multiple of its sum of digits (72).

It is not an unprimeable number, because it can be changed into a prime (1999999657) 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, 114775 + ... + 131046.

Almost surely, 2^1999999656 is an apocalyptic number.

It is an amenable number.

1999999656 is an abundant number, since it is smaller than the sum of its proper divisors (3464623404).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1999999656 is a wasteful number, since it uses less digits than its factorization.

1999999656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245946 (or 245939 counting only the distinct ones).

The product of its digits is 95659380, while the sum is 72.

The square root of 1999999656 is about 44721.3557039587. The cubic root of 1999999656 is about 1259.9209776594.

The spelling of 1999999656 in words is "one billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, six hundred fifty-six".