681969780 has 144 divisors (see below), whose sum is σ = 2238897024. Its totient is φ = 173923200.

The previous prime is 681969767. The next prime is 681969781. The reversal of 681969780 is 87969186.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681969781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 108730 + ... + 114830.

It is an arithmetic number, because the mean of its divisors is an integer number (15547896).

Almost surely, 2^681969780 is an apocalyptic number.

681969780 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 681969780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1119448512).

681969780 is an abundant number, since it is smaller than the sum of its proper divisors (1556927244).

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

681969780 is a wasteful number, since it uses less digits than its factorization.

681969780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6148 (or 6134 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 54.

The square root of 681969780 is about 26114.5511161881. The cubic root of 681969780 is about 880.2142126585.

The spelling of 681969780 in words is "six hundred eighty-one million, nine hundred sixty-nine thousand, seven hundred eighty".