61981680 has 80 divisors (see below), whose sum is σ = 194121504. Its totient is φ = 16358400.

The previous prime is 61981663. The next prime is 61981681. The reversal of 61981680 is 8618916.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61981681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22962 + ... + 25518.

Almost surely, 2^61981680 is an apocalyptic number.

61981680 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 61981680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97060752).

61981680 is an abundant number, since it is smaller than the sum of its proper divisors (132139824).

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

61981680 is a wasteful number, since it uses less digits than its factorization.

61981680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2674 (or 2668 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 61981680 is about 7872.8444669001. The cubic root of 61981680 is about 395.7501740233.

The spelling of 61981680 in words is "sixty-one million, nine hundred eighty-one thousand, six hundred eighty".