61653968640 has 576 divisors, whose sum is σ = 240743301120. Its totient is φ = 14817116160.

The previous prime is 61653968627. The next prime is 61653968681. The reversal of 61653968640 is 4686935616.

61653968640 is a `hidden beast` number, since 6 + 1 + 6 + 539 + 68 + 6 + 40 = 666.

61653968640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 48279682 + ... + 48280958.

It is an arithmetic number, because the mean of its divisors is an integer number (417957120).

Almost surely, 2^61653968640 is an apocalyptic number.

61653968640 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 61653968640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120371650560).

61653968640 is an abundant number, since it is smaller than the sum of its proper divisors (179089332480).

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

61653968640 is a wasteful number, since it uses less digits than its factorization.

61653968640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1445 (or 1425 counting only the distinct ones).

The product of its (nonzero) digits is 5598720, while the sum is 54.

The spelling of 61653968640 in words is "sixty-one billion, six hundred fifty-three million, nine hundred sixty-eight thousand, six hundred forty".