61555140 has 60 divisors (see below), whose sum is σ = 193105836. Its totient is φ = 16414272.

The previous prime is 61555127. The next prime is 61555163. The reversal of 61555140 is 4155516.

It is a happy number.

61555140 is a `hidden beast` number, since 615 + 5 + 5 + 1 + 40 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 44116164 + 17438976 = 6642^2 + 4176^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 17379 + ... + 20618.

Almost surely, 2^61555140 is an apocalyptic number.

61555140 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61555140 is an abundant number, since it is smaller than the sum of its proper divisors (131550696).

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

61555140 is a wasteful number, since it uses less digits than its factorization.

61555140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38018 (or 38007 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The square root of 61555140 is about 7845.7083810195. The cubic root of 61555140 is about 394.8402708341.

It can be divided in two parts, 615 and 55140, that added together give a palindrome (55755).

The spelling of 61555140 in words is "sixty-one million, five hundred fifty-five thousand, one hundred forty".