61557534144 has 224 divisors, whose sum is σ = 191939143680. Its totient is φ = 19304524800.

The previous prime is 61557534131. The next prime is 61557534151. The reversal of 61557534144 is 44143575516.

It is a happy number.

61557534144 is a `hidden beast` number, since 6 + 1 + 5 + 575 + 34 + 1 + 44 = 666.

61557534144 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 61557534144.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2411689 + ... + 2437079.

Almost surely, 2^61557534144 is an apocalyptic number.

61557534144 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 61557534144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95969571840).

61557534144 is an abundant number, since it is smaller than the sum of its proper divisors (130381609536).

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

61557534144 is a wasteful number, since it uses less digits than its factorization.

61557534144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25496 (or 25480 counting only the distinct ones).

The product of its digits is 1008000, while the sum is 45.

The spelling of 61557534144 in words is "sixty-one billion, five hundred fifty-seven million, five hundred thirty-four thousand, one hundred forty-four".