681240388 has 24 divisors (see below), whose sum is σ = 1273483512. Its totient is φ = 317743104.

The previous prime is 681240353. The next prime is 681240457. The reversal of 681240388 is 883042186.

It can be written as a sum of positive squares in 4 ways, for example, as 41757444 + 639482944 = 6462^2 + 25288^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 681240388.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36645 + ... + 52012.

It is an arithmetic number, because the mean of its divisors is an integer number (53061813).

Almost surely, 2^681240388 is an apocalyptic number.

681240388 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

681240388 is a deficient number, since it is larger than the sum of its proper divisors (592243124).

681240388 is a wasteful number, since it uses less digits than its factorization.

681240388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88791 (or 88789 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 40.

The square root of 681240388 is about 26100.5821391018. The cubic root of 681240388 is about 879.9002934555.

The spelling of 681240388 in words is "six hundred eighty-one million, two hundred forty thousand, three hundred eighty-eight".