61531780 has 12 divisors (see below), whose sum is σ = 129216780. Its totient is φ = 24612704.

The previous prime is 61531759. The next prime is 61531793. The reversal of 61531780 is 8713516.

61531780 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 43007364 + 18524416 = 6558^2 + 4304^2 .

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 3 ways as a sum of consecutive naturals, for example, 1538275 + ... + 1538314.

It is an arithmetic number, because the mean of its divisors is an integer number (10768065).

Almost surely, 2^61531780 is an apocalyptic number.

It is an amenable number.

61531780 is an abundant number, since it is smaller than the sum of its proper divisors (67685000).

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

61531780 is a wasteful number, since it uses less digits than its factorization.

61531780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3076598 (or 3076596 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 31.

The square root of 61531780 is about 7844.2195277797. The cubic root of 61531780 is about 394.7903175958.

The spelling of 61531780 in words is "sixty-one million, five hundred thirty-one thousand, seven hundred eighty".