61009920 has 156 divisors (see below), whose sum is σ = 212114136. Its totient is φ = 16220160.

The previous prime is 61009919. The next prime is 61009937. The reversal of 61009920 is 2990016.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 184155 + ... + 184485.

It is an arithmetic number, because the mean of its divisors is an integer number (1359706).

Almost surely, 2^61009920 is an apocalyptic number.

61009920 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 61009920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106057068).

61009920 is an abundant number, since it is smaller than the sum of its proper divisors (151104216).

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

61009920 is a wasteful number, since it uses less digits than its factorization.

61009920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366 (or 341 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 61009920 is about 7810.8847130143. The cubic root of 61009920 is about 393.6710559799.

Adding to 61009920 its reverse (2990016), we get a palindrome (63999936).

The spelling of 61009920 in words is "sixty-one million, nine thousand, nine hundred twenty".