61681680 has 60 divisors (see below), whose sum is σ = 207150060. Its totient is φ = 16448256.

The previous prime is 61681649. The next prime is 61681681. The reversal of 61681680 is 8618616.

It can be written as a sum of positive squares in 2 ways, for example, as 26255376 + 35426304 = 5124^2 + 5952^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (61681681) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42115 + ... + 43554.

It is an arithmetic number, because the mean of its divisors is an integer number (3452501).

Almost surely, 2^61681680 is an apocalyptic number.

61681680 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61681680 is an abundant number, since it is smaller than the sum of its proper divisors (145468380).

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

61681680 is a wasteful number, since it uses less digits than its factorization.

61681680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85688 (or 85679 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 61681680 is about 7853.7685221809. The cubic root of 61681680 is about 395.1106457113.

The spelling of 61681680 in words is "sixty-one million, six hundred eighty-one thousand, six hundred eighty".