61720289280 has 896 divisors, whose sum is σ = 243747584640. Its totient is φ = 14906032128.

The previous prime is 61720289261. The next prime is 61720289291. The reversal of 61720289280 is 8298202716.

61720289280 is a `hidden beast` number, since 617 + 2 + 0 + 2 + 8 + 9 + 28 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a nialpdrome in base 12.

It is a zygodrome in base 12.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1164533734 + ... + 1164533786.

It is an arithmetic number, because the mean of its divisors is an integer number (272039715).

Almost surely, 2^61720289280 is an apocalyptic number.

61720289280 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 61720289280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121873792320).

61720289280 is an abundant number, since it is smaller than the sum of its proper divisors (182027295360).

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

61720289280 is an frugal number, since it uses more digits than its factorization.

61720289280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118 (or 76 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The spelling of 61720289280 in words is "sixty-one billion, seven hundred twenty million, two hundred eighty-nine thousand, two hundred eighty".