641691072 has 336 divisors, whose sum is σ = 2165689344. Its totient is φ = 188179200.

The previous prime is 641691031. The next prime is 641691079. The reversal of 641691072 is 270196146.

641691072 is a `hidden beast` number, since 641 + 6 + 9 + 1 + 0 + 7 + 2 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641691079) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 20699697 + ... + 20699727.

It is an arithmetic number, because the mean of its divisors is an integer number (6445504).

Almost surely, 2^641691072 is an apocalyptic number.

641691072 is a gapful number since it is divisible by the number (62) 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 641691072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1082844672).

641691072 is an abundant number, since it is smaller than the sum of its proper divisors (1523998272).

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

641691072 is an equidigital number, since it uses as much as digits as its factorization.

641691072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 641691072 is about 25331.6219772836. The cubic root of 641691072 is about 862.5322301756.

The spelling of 641691072 in words is "six hundred forty-one million, six hundred ninety-one thousand, seventy-two".