641981730 has 32 divisors (see below), whose sum is σ = 1659276864. Its totient is φ = 158026176.

The previous prime is 641981719. The next prime is 641981737. The reversal of 641981730 is 37189146.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (641981737) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 822664 + ... + 823443.

It is an arithmetic number, because the mean of its divisors is an integer number (51852402).

Almost surely, 2^641981730 is an apocalyptic number.

641981730 is an abundant number, since it is smaller than the sum of its proper divisors (1017295134).

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

641981730 is a wasteful number, since it uses less digits than its factorization.

641981730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1646130.

The product of its (nonzero) digits is 36288, while the sum is 39.

The square root of 641981730 is about 25337.3583863827. The cubic root of 641981730 is about 862.6624403141.

The spelling of 641981730 in words is "six hundred forty-one million, nine hundred eighty-one thousand, seven hundred thirty".