61543440 has 120 divisors (see below), whose sum is σ = 236228928. Its totient is φ = 14065920.

The previous prime is 61543429. The next prime is 61543477. The reversal of 61543440 is 4434516.

61543440 is a `hidden beast` number, since 615 + 4 + 3 + 4 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1066 + ... + 11145.

Almost surely, 2^61543440 is an apocalyptic number.

61543440 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 61543440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118114464).

61543440 is an abundant number, since it is smaller than the sum of its proper divisors (174685488).

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

61543440 is a wasteful number, since it uses less digits than its factorization.

61543440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12237 (or 12228 counting only the distinct ones).

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

The square root of 61543440 is about 7844.9627150166. The cubic root of 61543440 is about 394.8152530269.

Adding to 61543440 its reverse (4434516), we get a palindrome (65977956).

The spelling of 61543440 in words is "sixty-one million, five hundred forty-three thousand, four hundred forty".