61578720 has 288 divisors, whose sum is σ = 247665600. Its totient is φ = 13639680.

The previous prime is 61578701. The next prime is 61578733. The reversal of 61578720 is 2787516.

61578720 is a `hidden beast` number, since 61 + 578 + 7 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 413206 + ... + 413354.

It is an arithmetic number, because the mean of its divisors is an integer number (859950).

Almost surely, 2^61578720 is an apocalyptic number.

61578720 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 61578720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123832800).

61578720 is an abundant number, since it is smaller than the sum of its proper divisors (186086880).

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

61578720 is a wasteful number, since it uses less digits than its factorization.

61578720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218 (or 207 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

The square root of 61578720 is about 7847.2109695101. The cubic root of 61578720 is about 394.8906817069.

The spelling of 61578720 in words is "sixty-one million, five hundred seventy-eight thousand, seven hundred twenty".