61545440 has 144 divisors (see below), whose sum is σ = 169891344. Its totient is φ = 21063680.

The previous prime is 61545439. The next prime is 61545481. The reversal of 61545440 is 4454516.

It is a congruent number.

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, 3620312 + ... + 3620328.

It is an arithmetic number, because the mean of its divisors is an integer number (1179801).

Almost surely, 2^61545440 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 61545440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84945672).

61545440 is an abundant number, since it is smaller than the sum of its proper divisors (108345904).

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

61545440 is a wasteful number, since it uses less digits than its factorization.

61545440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82 (or 35 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 29.

The square root of 61545440 is about 7845.0901843127. The cubic root of 61545440 is about 394.8195297998.

Adding to 61545440 its reverse (4454516), we get a palindrome (65999956).

The spelling of 61545440 in words is "sixty-one million, five hundred forty-five thousand, four hundred forty".