61215140 has 48 divisors (see below), whose sum is σ = 147471744. Its totient is φ = 20908800.

The previous prime is 61215127. The next prime is 61215149. The reversal of 61215140 is 4151216.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (61215149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45680 + ... + 47000.

It is an arithmetic number, because the mean of its divisors is an integer number (3072328).

Almost surely, 2^61215140 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 61215140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73735872).

61215140 is an abundant number, since it is smaller than the sum of its proper divisors (86256604).

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

61215140 is a wasteful number, since it uses less digits than its factorization.

61215140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1668 (or 1666 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 61215140 is about 7824.0104805656. The cubic root of 61215140 is about 394.1119611041. Note that the first 3 decimals are identical.

Adding to 61215140 its reverse (4151216), we get a palindrome (65366356).

The spelling of 61215140 in words is "sixty-one million, two hundred fifteen thousand, one hundred forty".