197807778 has 64 divisors (see below), whose sum is σ = 504483840. Its totient is φ = 56278800.

The previous prime is 197807777. The next prime is 197807789. The reversal of 197807778 is 877708791.

197807778 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (197807777) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 101473 + ... + 103403.

It is an arithmetic number, because the mean of its divisors is an integer number (7882560).

Almost surely, 2^197807778 is an apocalyptic number.

197807778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 197807778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (252241920).

197807778 is an abundant number, since it is smaller than the sum of its proper divisors (306676062).

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

197807778 is a wasteful number, since it uses less digits than its factorization.

197807778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2220 (or 2214 counting only the distinct ones).

The product of its (nonzero) digits is 1382976, while the sum is 54.

The square root of 197807778 is about 14064.4153095676. The cubic root of 197807778 is about 582.6589942180.

The spelling of 197807778 in words is "one hundred ninety-seven million, eight hundred seven thousand, seven hundred seventy-eight".