61509975280 has 320 divisors, whose sum is σ = 174138854400. Its totient is φ = 19957432320.

The previous prime is 61509975277. The next prime is 61509975283. The reversal of 61509975280 is 8257990516.

It is an interprime number because it is at equal distance from previous prime (61509975277) and next prime (61509975283).

It is a super-2 number, since 2×61509975280² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61509975283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 23849031 + ... + 23851609.

It is an arithmetic number, because the mean of its divisors is an integer number (544183920).

Almost surely, 2^61509975280 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61509975280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87069427200).

61509975280 is an abundant number, since it is smaller than the sum of its proper divisors (112628879120).

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

61509975280 is a wasteful number, since it uses less digits than its factorization.

61509975280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2712 (or 2706 counting only the distinct ones).

The product of its (nonzero) digits is 1360800, while the sum is 52.

The spelling of 61509975280 in words is "sixty-one billion, five hundred nine million, nine hundred seventy-five thousand, two hundred eighty".