61188767640 has 1152 divisors, whose sum is σ = 275347537920. Its totient is φ = 11583129600.

The previous prime is 61188767551. The next prime is 61188767699. The reversal of 61188767640 is 4676788116.

It is a super-2 number, since 2×61188767640² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 320359945 + ... + 320360135.

It is an arithmetic number, because the mean of its divisors is an integer number (239016960).

Almost surely, 2^61188767640 is an apocalyptic number.

61188767640 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 61188767640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137673768960).

61188767640 is an abundant number, since it is smaller than the sum of its proper divisors (214158770280).

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

61188767640 is a wasteful number, since it uses less digits than its factorization.

61188767640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 373 (or 359 counting only the distinct ones).

The product of its (nonzero) digits is 2709504, while the sum is 54.

It can be divided in two parts, 61188 and 767640, that added together give a palindrome (828828).

The spelling of 61188767640 in words is "sixty-one billion, one hundred eighty-eight million, seven hundred sixty-seven thousand, six hundred forty".