61881810 has 32 divisors (see below), whose sum is σ = 148761792. Its totient is φ = 16474560.

The previous prime is 61881779. The next prime is 61881821. The reversal of 61881810 is 1818816.

It is a super-2 number, since 2×61881810² = 7658716817752200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22300 + ... + 24920.

It is an arithmetic number, because the mean of its divisors is an integer number (4648806).

Almost surely, 2^61881810 is an apocalyptic number.

61881810 is an abundant number, since it is smaller than the sum of its proper divisors (86879982).

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

61881810 is a wasteful number, since it uses less digits than its factorization.

61881810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3418.

The product of its (nonzero) digits is 3072, while the sum is 33.

The square root of 61881810 is about 7866.4992213818. The cubic root of 61881810 is about 395.5375046411.

It can be divided in two parts, 618818 and 10, that added together give a triangular number (618828 = T₁₁₁₂).

The spelling of 61881810 in words is "sixty-one million, eight hundred eighty-one thousand, eight hundred ten".