61117781 has 8 divisors (see below), whose sum is σ = 61642944. Its totient is φ = 60595360.

The previous prime is 61117769. The next prime is 61117783. The reversal of 61117781 is 18771116.

61117781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61117781 is a prime.

It is a super-2 number, since 2×61117781² = 7470766308727922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61117783) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 73490 + ... + 74316.

It is an arithmetic number, because the mean of its divisors is an integer number (7705368).

Almost surely, 2^61117781 is an apocalyptic number.

It is an amenable number.

61117781 is a deficient number, since it is larger than the sum of its proper divisors (525163).

61117781 is a wasteful number, since it uses less digits than its factorization.

61117781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1371.

The product of its digits is 2352, while the sum is 32.

The square root of 61117781 is about 7817.7861955927. The cubic root of 61117781 is about 393.9029131120.

Adding to 61117781 its reverse (18771116), we get a palindrome (79888897).

The spelling of 61117781 in words is "sixty-one million, one hundred seventeen thousand, seven hundred eighty-one".