197981820 has 168 divisors, whose sum is σ = 641949504. Its totient is φ = 51228288.

The previous prime is 197981807. The next prime is 197981831. The reversal of 197981820 is 28189791.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 539277 + ... + 539643.

It is an arithmetic number, because the mean of its divisors is an integer number (3821128).

Almost surely, 2^197981820 is an apocalyptic number.

197981820 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 197981820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (320974752).

197981820 is an abundant number, since it is smaller than the sum of its proper divisors (443967684).

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

197981820 is a wasteful number, since it uses less digits than its factorization.

197981820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431 (or 414 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 45.

The square root of 197981820 is about 14070.6012664705. The cubic root of 197981820 is about 582.8298291081.

The spelling of 197981820 in words is "one hundred ninety-seven million, nine hundred eighty-one thousand, eight hundred twenty".