61640 has 32 divisors (see below), whose sum is σ = 146880. Its totient is φ = 23232.

The previous prime is 61637. The next prime is 61643. The reversal of 61640 is 4616.

It is an interprime number because it is at equal distance from previous prime (61637) and next prime (61643).

It is not an unprimeable number, because it can be changed into a prime (61643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 887 + ... + 953.

It is an arithmetic number, because the mean of its divisors is an integer number (4590).

2⁶¹⁶⁴⁰ 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 61640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73440).

61640 is an abundant number, since it is smaller than the sum of its proper divisors (85240).

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

61640 is a wasteful number, since it uses less digits than its factorization.

61640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101 (or 97 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 61640 is about 248.2740421389. The cubic root of 61640 is about 39.5021629964.

It can be divided in two parts, 616 and 40, that added together give a palindrome (656).

The spelling of 61640 in words is "sixty-one thousand, six hundred forty".