61781382 has 48 divisors (see below), whose sum is σ = 145939248. Its totient is φ = 18774720.

The previous prime is 61781371. The next prime is 61781389. The reversal of 61781382 is 28318716.

61781382 = 2174² + 2175² + ... + 2186².

61781382 is a `hidden beast` number, since 617 + 8 + 1 + 38 + 2 = 666.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61781389) 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, 17832 + ... + 21012.

It is an arithmetic number, because the mean of its divisors is an integer number (3040401).

Almost surely, 2^61781382 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61781382, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72969624).

61781382 is an abundant number, since it is smaller than the sum of its proper divisors (84157866).

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

61781382 is a wasteful number, since it uses less digits than its factorization.

61781382 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3285 (or 3282 counting only the distinct ones).

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

The square root of 61781382 is about 7860.1133579612. The cubic root of 61781382 is about 395.3234161567.

The spelling of 61781382 in words is "sixty-one million, seven hundred eighty-one thousand, three hundred eighty-two".