61538440 has 16 divisors (see below), whose sum is σ = 138461580. Its totient is φ = 24615360.

The previous prime is 61538431. The next prime is 61538443. The reversal of 61538440 is 4483516.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 61121124 + 417316 = 7818^2 + 646^2 .

It is not an unprimeable number, because it can be changed into a prime (61538443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 769191 + ... + 769270.

Almost surely, 2^61538440 is an apocalyptic number.

It is an amenable number.

61538440 is an abundant number, since it is smaller than the sum of its proper divisors (76923140).

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

61538440 is a wasteful number, since it uses less digits than its factorization.

61538440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1538472 (or 1538468 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 61538440 is about 7844.6440327143. The cubic root of 61538440 is about 394.8045606892.

The spelling of 61538440 in words is "sixty-one million, five hundred thirty-eight thousand, four hundred forty".