61781904 has 60 divisors (see below), whose sum is σ = 173491500. Its totient is φ = 20524032.

The previous prime is 61781903. The next prime is 61781917. The reversal of 61781904 is 40918716.

It can be written as a sum of positive squares in 2 ways, for example, as 56250000 + 5531904 = 7500^2 + 2352^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (61781903) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 58372 + ... + 59420.

It is an arithmetic number, because the mean of its divisors is an integer number (2891525).

Almost surely, 2^61781904 is an apocalyptic number.

It is an amenable number.

61781904 is an abundant number, since it is smaller than the sum of its proper divisors (111709596).

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

61781904 is a wasteful number, since it uses less digits than its factorization.

61781904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1472 (or 1463 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 61781904 is about 7860.1465635190. The cubic root of 61781904 is about 395.3245295355.

The spelling of 61781904 in words is "sixty-one million, seven hundred eighty-one thousand, nine hundred four".