61640080 has 60 divisors (see below), whose sum is σ = 149170140. Its totient is φ = 23659776.

The previous prime is 61640071. The next prime is 61640083. The reversal of 61640080 is 8004616.

It can be written as a sum of positive squares in 2 ways, for example, as 27206656 + 34433424 = 5216^2 + 5868^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61640083) 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, 378079 + ... + 378241.

It is an arithmetic number, because the mean of its divisors is an integer number (2486169).

Almost surely, 2^61640080 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61640080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (74585070).

61640080 is an abundant number, since it is smaller than the sum of its proper divisors (87530060).

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

61640080 is a wasteful number, since it uses less digits than its factorization.

61640080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368 (or 199 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 61640080 is about 7851.1196653726. The cubic root of 61640080 is about 395.0218008584.

Adding to 61640080 its reverse (8004616), we get a palindrome (69644696).

The spelling of 61640080 in words is "sixty-one million, six hundred forty thousand, eighty".