61531155 has 48 divisors (see below), whose sum is σ = 122566080. Its totient is φ = 27972864.

The previous prime is 61531147. The next prime is 61531163. The reversal of 61531155 is 55113516.

61531155 is a `hidden beast` number, since 615 + 31 + 15 + 5 = 666.

61531155 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (61531147) and next prime (61531163).

It is not a de Polignac number, because 61531155 - 2³ = 61531147 is a prime.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 71709 + ... + 72561.

It is an arithmetic number, because the mean of its divisors is an integer number (2553460).

Almost surely, 2^61531155 is an apocalyptic number.

61531155 is a deficient number, since it is larger than the sum of its proper divisors (61034925).

61531155 is a wasteful number, since it uses less digits than its factorization.

61531155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1100 (or 1097 counting only the distinct ones).

The product of its digits is 2250, while the sum is 27.

The square root of 61531155 is about 7844.1796894258. The cubic root of 61531155 is about 394.7889809165.

The spelling of 61531155 in words is "sixty-one million, five hundred thirty-one thousand, one hundred fifty-five".