61601312640 has 256 divisors, whose sum is σ = 229880125440. Its totient is φ = 13736755200.

The previous prime is 61601312623. The next prime is 61601312653. The reversal of 61601312640 is 4621310616.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 61601312598 and 61601312607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 495145 + ... + 606935.

It is an arithmetic number, because the mean of its divisors is an integer number (897969240).

Almost surely, 2^61601312640 is an apocalyptic number.

61601312640 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 61601312640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114940062720).

61601312640 is an abundant number, since it is smaller than the sum of its proper divisors (168278812800).

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

61601312640 is a wasteful number, since it uses less digits than its factorization.

61601312640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111861 (or 111849 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 30.

The spelling of 61601312640 in words is "sixty-one billion, six hundred one million, three hundred twelve thousand, six hundred forty".