61011720 has 384 divisors, whose sum is σ = 258785280. Its totient is φ = 12096000.

The previous prime is 61011697. The next prime is 61011733. The reversal of 61011720 is 2711016.

61011720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Cunningham number, because it is equal to 7811²-1.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 61011693 and 61011702.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 859285 + ... + 859355.

It is an arithmetic number, because the mean of its divisors is an integer number (673920).

Almost surely, 2^61011720 is an apocalyptic number.

61011720 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 61011720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129392640).

61011720 is an abundant number, since it is smaller than the sum of its proper divisors (197773560).

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

61011720 is a wasteful number, since it uses less digits than its factorization.

61011720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 18.

The square root of 61011720 is about 7810.9999359877. Note that the first 4 decimals coincide. The cubic root of 61011720 is about 393.6749274865.

Adding to 61011720 its reverse (2711016), we get a palindrome (63722736).

The spelling of 61011720 in words is "sixty-one million, eleven thousand, seven hundred twenty".