1668721870 has 32 divisors (see below), whose sum is σ = 3186278208. Its totient is φ = 627061248.

The previous prime is 1668721823. The next prime is 1668721877. The reversal of 1668721870 is 781278661.

It is a self number, because there is not a number n which added to its sum of digits gives 1668721870.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668721877) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 85879 + ... + 103501.

It is an arithmetic number, because the mean of its divisors is an integer number (99571194).

Almost surely, 2^1668721870 is an apocalyptic number.

1668721870 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1668721870 is a deficient number, since it is larger than the sum of its proper divisors (1517556338).

1668721870 is a wasteful number, since it uses less digits than its factorization.

1668721870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18204.

The product of its (nonzero) digits is 225792, while the sum is 46.

The square root of 1668721870 is about 40849.9922888610. The cubic root of 1668721870 is about 1186.1182439146.

The spelling of 1668721870 in words is "one billion, six hundred sixty-eight million, seven hundred twenty-one thousand, eight hundred seventy".