61911357776640 has 864 divisors, whose sum is σ = 232913775144960. Its totient is φ = 15125866905600.

The previous prime is 61911357776629. The next prime is 61911357776647. The reversal of 61911357776640 is 4667775311916.

61911357776640 is a `hidden beast` number, since 6 + 1 + 9 + 1 + 13 + 577 + 7 + 6 + 6 + 40 = 666.

It is not an unprimeable number, because it can be changed into a prime (61911357776647) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 15830056285 + ... + 15830060195.

It is an arithmetic number, because the mean of its divisors is an integer number (269576128640).

Almost surely, 2^{61911357776640} is an apocalyptic number.

61911357776640 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 61911357776640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116456887572480).

61911357776640 is an abundant number, since it is smaller than the sum of its proper divisors (171002417368320).

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

61911357776640 is a wasteful number, since it uses less digits than its factorization.

61911357776640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6321 (or 6304 counting only the distinct ones).

The product of its (nonzero) digits is 40007520, while the sum is 63.

The spelling of 61911357776640 in words is "sixty-one trillion, nine hundred eleven billion, three hundred fifty-seven million, seven hundred seventy-six thousand, six hundred forty".