61597609920 has 840 divisors, whose sum is σ = 278121800880. Its totient is φ = 12796600320.

The previous prime is 61597609903. The next prime is 61597609921. The reversal of 61597609920 is 2990679516.

61597609920 is a `hidden beast` number, since 6 + 1 + 5 + 9 + 7 + 609 + 9 + 20 = 666.

61597609920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (840).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61597609921) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 13968676 + ... + 13973084.

It is an arithmetic number, because the mean of its divisors is an integer number (331097382).

Almost surely, 2^61597609920 is an apocalyptic number.

61597609920 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 61597609920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139060900440).

61597609920 is an abundant number, since it is smaller than the sum of its proper divisors (216524190960).

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

61597609920 is a wasteful number, since it uses less digits than its factorization.

61597609920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4463 (or 4437 counting only the distinct ones).

The product of its (nonzero) digits is 1837080, while the sum is 54.

The spelling of 61597609920 in words is "sixty-one billion, five hundred ninety-seven million, six hundred nine thousand, nine hundred twenty".