61345440 has 288 divisors, whose sum is σ = 235282320. Its totient is φ = 14450688.

The previous prime is 61345423. The next prime is 61345441. The reversal of 61345440 is 4454316.

61345440 is a `hidden beast` number, since 613 + 4 + 5 + 4 + 40 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 2547216 + 58798224 = 1596^2 + 7668^2 .

It is a tau number, because it is divible by the number of its divisors (288).

It is not an unprimeable number, because it can be changed into a prime (61345441) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 542824 + ... + 542936.

Almost surely, 2^61345440 is an apocalyptic number.

61345440 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 61345440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117641160).

61345440 is an abundant number, since it is smaller than the sum of its proper divisors (173936880).

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

61345440 is a wasteful number, since it uses less digits than its factorization.

61345440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176 (or 165 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 61345440 is about 7832.3329857712. The cubic root of 61345440 is about 394.3913930429.

Adding to 61345440 its reverse (4454316), we get a palindrome (65799756).

The spelling of 61345440 in words is "sixty-one million, three hundred forty-five thousand, four hundred forty".