61540038144 has 640 divisors, whose sum is σ = 210361536000. Its totient is φ = 17605361664.

The previous prime is 61540038143. The next prime is 61540038173. The reversal of 61540038144 is 44183004516.

61540038144 is a `hidden beast` number, since 615 + 4 + 0 + 0 + 38 + 1 + 4 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 61540038099 and 61540038108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61540038143) 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 63 ways as a sum of consecutive naturals, for example, 228773242 + ... + 228773510.

It is an arithmetic number, because the mean of its divisors is an integer number (328689900).

Almost surely, 2^61540038144 is an apocalyptic number.

61540038144 is a gapful number since it is divisible by the number (64) 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 61540038144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105180768000).

61540038144 is an abundant number, since it is smaller than the sum of its proper divisors (148821497856).

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

61540038144 is a wasteful number, since it uses less digits than its factorization.

61540038144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395 (or 373 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The spelling of 61540038144 in words is "sixty-one billion, five hundred forty million, thirty-eight thousand, one hundred forty-four".