61756309440 has 448 divisors, whose sum is σ = 249682406400. Its totient is φ = 14076260352.

The previous prime is 61756309427. The next prime is 61756309493. The reversal of 61756309440 is 4490365716.

61756309440 is a `hidden beast` number, since 6 + 1 + 7 + 5 + 630 + 9 + 4 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (448).

It is a super-2 number, since 2×61756309440² (a number of 22 digits) contains 22 as substring.

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

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, 25339902 + ... + 25342338.

It is an arithmetic number, because the mean of its divisors is an integer number (557326800).

Almost surely, 2^61756309440 is an apocalyptic number.

61756309440 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 61756309440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124841203200).

61756309440 is an abundant number, since it is smaller than the sum of its proper divisors (187926096960).

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

61756309440 is a wasteful number, since it uses less digits than its factorization.

61756309440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2889 (or 2873 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 45.

The spelling of 61756309440 in words is "sixty-one billion, seven hundred fifty-six million, three hundred nine thousand, four hundred forty".