681948540 has 576 divisors, whose sum is σ = 2817884160. Its totient is φ = 129392640.

The previous prime is 681948511. The next prime is 681948569. The reversal of 681948540 is 45849186.

681948540 is a `hidden beast` number, since 68 + 1 + 9 + 48 + 540 = 666.

It is an interprime number because it is at equal distance from previous prime (681948511) and next prime (681948569).

It is a super-2 number, since 2×681948540² = 930107622416263200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 8632221 + ... + 8632299.

It is an arithmetic number, because the mean of its divisors is an integer number (4892160).

Almost surely, 2^681948540 is an apocalyptic number.

681948540 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 681948540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1408942080).

681948540 is an abundant number, since it is smaller than the sum of its proper divisors (2135935620).

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

681948540 is a wasteful number, since it uses less digits than its factorization.

681948540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 157 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The square root of 681948540 is about 26114.1444431940. The cubic root of 681948540 is about 880.2050744511.

The spelling of 681948540 in words is "six hundred eighty-one million, nine hundred forty-eight thousand, five hundred forty".