1897172806 has 4 divisors (see below), whose sum is σ = 2845759212. Its totient is φ = 948586402.

The previous prime is 1897172791. The next prime is 1897172821. The reversal of 1897172806 is 6082717981.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1897172791) and next prime (1897172821).

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 1897172806.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 474293200 + ... + 474293203.

It is an arithmetic number, because the mean of its divisors is an integer number (711439803).

Almost surely, 2^1897172806 is an apocalyptic number.

1897172806 is a deficient number, since it is larger than the sum of its proper divisors (948586406).

1897172806 is an equidigital number, since it uses as much as digits as its factorization.

1897172806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 948586405.

The product of its (nonzero) digits is 338688, while the sum is 49.

The square root of 1897172806 is about 43556.5472231213. The cubic root of 1897172806 is about 1237.9476990614.

The spelling of 1897172806 in words is "one billion, eight hundred ninety-seven million, one hundred seventy-two thousand, eight hundred six".