61028640 has 240 divisors, whose sum is σ = 228872952. Its totient is φ = 15261696.

The previous prime is 61028621. The next prime is 61028641. The reversal of 61028640 is 4682016.

61028640 is a `hidden beast` number, since 6 + 10 + 2 + 8 + 640 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 47279376 + 13749264 = 6876^2 + 3708^2 .

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61028641) 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 39 ways as a sum of consecutive naturals, for example, 220182 + ... + 220458.

Almost surely, 2^61028640 is an apocalyptic number.

61028640 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 61028640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114436476).

61028640 is an abundant number, since it is smaller than the sum of its proper divisors (167844312).

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

61028640 is a wasteful number, since it uses less digits than its factorization.

61028640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321 (or 304 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 61028640 is about 7812.0829488684. The cubic root of 61028640 is about 393.7113159275.

The spelling of 61028640 in words is "sixty-one million, twenty-eight thousand, six hundred forty".