61868781 has 48 divisors (see below), whose sum is σ = 102001536. Its totient is φ = 35849088.

The previous prime is 61868759. The next prime is 61868809. The reversal of 61868781 is 18786816.

61868781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 61868781 - 2⁵ = 61868749 is a prime.

It is a super-2 number, since 2×61868781² = 7655492124851922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61868711) by changing a digit.

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, 223215 + ... + 223491.

It is an arithmetic number, because the mean of its divisors is an integer number (2125032).

Almost surely, 2^61868781 is an apocalyptic number.

It is an amenable number.

61868781 is a deficient number, since it is larger than the sum of its proper divisors (40132755).

61868781 is a wasteful number, since it uses less digits than its factorization.

61868781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402 (or 399 counting only the distinct ones).

The product of its digits is 129024, while the sum is 45.

The square root of 61868781 is about 7865.6710457532. The cubic root of 61868781 is about 395.5097430104.

The spelling of 61868781 in words is "sixty-one million, eight hundred sixty-eight thousand, seven hundred eighty-one".