61728381 has 24 divisors (see below), whose sum is σ = 104753376. Its totient is φ = 34532640.

The previous prime is 61728367. The next prime is 61728391. The reversal of 61728381 is 18382716.

61728381 is a `hidden beast` number, since 617 + 2 + 8 + 38 + 1 = 666.

It is not a de Polignac number, because 61728381 - 2¹¹ = 61726333 is a prime.

It is a super-2 number, since 2×61728381² = 7620786041762322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61728391) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22695 + ... + 25268.

It is an arithmetic number, because the mean of its divisors is an integer number (4364724).

Almost surely, 2^61728381 is an apocalyptic number.

It is an amenable number.

61728381 is a deficient number, since it is larger than the sum of its proper divisors (43024995).

61728381 is a wasteful number, since it uses less digits than its factorization.

61728381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47993 (or 47990 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 61728381 is about 7856.7411183009. The cubic root of 61728381 is about 395.2103371559.

The spelling of 61728381 in words is "sixty-one million, seven hundred twenty-eight thousand, three hundred eighty-one".