61155557280 has 576 divisors, whose sum is σ = 227257954560. Its totient is φ = 15509200896.

The previous prime is 61155557261. The next prime is 61155557329. The reversal of 61155557280 is 8275555116.

61155557280 is a `hidden beast` number, since 6 + 1 + 15 + 5 + 557 + 2 + 80 = 666.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

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

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 82308589 + ... + 82309331.

It is an arithmetic number, because the mean of its divisors is an integer number (394545060).

Almost surely, 2^61155557280 is an apocalyptic number.

61155557280 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 61155557280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113628977280).

61155557280 is an abundant number, since it is smaller than the sum of its proper divisors (166102397280).

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

61155557280 is a wasteful number, since it uses less digits than its factorization.

61155557280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 875 (or 855 counting only the distinct ones).

The product of its (nonzero) digits is 420000, while the sum is 45.

The spelling of 61155557280 in words is "sixty-one billion, one hundred fifty-five million, five hundred fifty-seven thousand, two hundred eighty".