61578220 has 48 divisors (see below), whose sum is σ = 142375968. Its totient is φ = 22184960.

The previous prime is 61578211. The next prime is 61578277. The reversal of 61578220 is 2287516.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23622 + ... + 26098.

It is an arithmetic number, because the mean of its divisors is an integer number (2966166).

Almost surely, 2^61578220 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 61578220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (71187984).

61578220 is an abundant number, since it is smaller than the sum of its proper divisors (80797748).

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

61578220 is a wasteful number, since it uses less digits than its factorization.

61578220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2610 (or 2608 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 61578220 is about 7847.1791109927. The cubic root of 61578220 is about 394.8896129077.

The spelling of 61578220 in words is "sixty-one million, five hundred seventy-eight thousand, two hundred twenty".