61213440 has 144 divisors (see below), whose sum is σ = 206035200. Its totient is φ = 15446016.

The previous prime is 61213433. The next prime is 61213441. The reversal of 61213440 is 4431216.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61213441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 72541 + ... + 73379.

It is an arithmetic number, because the mean of its divisors is an integer number (1430800).

Almost surely, 2^61213440 is an apocalyptic number.

61213440 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 61213440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103017600).

61213440 is an abundant number, since it is smaller than the sum of its proper divisors (144821760).

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

61213440 is a wasteful number, since it uses less digits than its factorization.

61213440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 882 (or 868 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 61213440 is about 7823.9018398750. The cubic root of 61213440 is about 394.1083127881.

Adding to 61213440 its reverse (4431216), we get a palindrome (65644656).

The spelling of 61213440 in words is "sixty-one million, two hundred thirteen thousand, four hundred forty".