1997807878 has 16 divisors (see below), whose sum is σ = 3272348160. Its totient is φ = 907203400.

The previous prime is 1997807849. The next prime is 1997807893. The reversal of 1997807878 is 8787087991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21358 + ... + 66721.

It is an arithmetic number, because the mean of its divisors is an integer number (204521760).

Almost surely, 2^1997807878 is an apocalyptic number.

1997807878 is a deficient number, since it is larger than the sum of its proper divisors (1274540282).

1997807878 is a wasteful number, since it uses less digits than its factorization.

1997807878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89123.

The product of its (nonzero) digits is 14224896, while the sum is 64.

The square root of 1997807878 is about 44696.8441615289. The cubic root of 1997807878 is about 1259.4605648387.

The spelling of 1997807878 in words is "one billion, nine hundred ninety-seven million, eight hundred seven thousand, eight hundred seventy-eight".