681379440 has 160 divisors (see below), whose sum is σ = 2425559040. Its totient is φ = 155000832.

The previous prime is 681379429. The next prime is 681379459. The reversal of 681379440 is 44973186.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 681379392 and 681379401.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 400672 + ... + 402368.

It is an arithmetic number, because the mean of its divisors is an integer number (15159744).

Almost surely, 2^681379440 is an apocalyptic number.

681379440 is a gapful number since it is divisible by the number (60) 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 681379440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1212779520).

681379440 is an abundant number, since it is smaller than the sum of its proper divisors (1744179600).

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

681379440 is a wasteful number, since it uses less digits than its factorization.

681379440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1959 (or 1953 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 42.

The square root of 681379440 is about 26103.2457751905. The cubic root of 681379440 is about 879.9601565983.

It can be divided in two parts, 68137 and 9440, that added together give a palindrome (77577).

The spelling of 681379440 in words is "six hundred eighty-one million, three hundred seventy-nine thousand, four hundred forty".