197421640 has 128 divisors (see below), whose sum is σ = 508677120. Its totient is φ = 68428800.

The previous prime is 197421619. The next prime is 197421641. The reversal of 197421640 is 46124791.

It is a junction number, because it is equal to n+sod(n) for n = 197421596 and 197421605.

It is not an unprimeable number, because it can be changed into a prime (197421641) 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, 596275 + ... + 596605.

It is an arithmetic number, because the mean of its divisors is an integer number (3974040).

Almost surely, 2^197421640 is an apocalyptic number.

197421640 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 197421640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (254338560).

197421640 is an abundant number, since it is smaller than the sum of its proper divisors (311255480).

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

197421640 is a wasteful number, since it uses less digits than its factorization.

197421640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 423 (or 419 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 197421640 is about 14050.6811222802. The cubic root of 197421640 is about 582.2796135589.

The spelling of 197421640 in words is "one hundred ninety-seven million, four hundred twenty-one thousand, six hundred forty".