197821440 has 308 divisors, whose sum is σ = 724908204. Its totient is φ = 51757056.

The previous prime is 197821411. The next prime is 197821487. The reversal of 197821440 is 44128791.

197821440 is a `hidden beast` number, since 197 + 8 + 21 + 440 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 107495424 + 90326016 = 10368^2 + 9504^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 197821395 and 197821404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 3732454 + ... + 3732506.

Almost surely, 2^197821440 is an apocalyptic number.

197821440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 197821440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (362454102).

197821440 is an abundant number, since it is smaller than the sum of its proper divisors (527086764).

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

197821440 is an frugal number, since it uses more digits than its factorization.

197821440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96 (or 63 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 197821440 is about 14064.9009950301. The cubic root of 197821440 is about 582.6724080888.

The spelling of 197821440 in words is "one hundred ninety-seven million, eight hundred twenty-one thousand, four hundred forty".