67784561 has 4 divisors (see below), whose sum is σ = 72998772. Its totient is φ = 62570352.

The previous prime is 67784557. The next prime is 67784567. The reversal of 67784561 is 16548776.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 43970161 + 23814400 = 6631^2 + 4880^2 .

It is not a de Polignac number, because 67784561 - 2² = 67784557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (67784567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2607086 + ... + 2607111.

It is an arithmetic number, because the mean of its divisors is an integer number (18249693).

Almost surely, 2^67784561 is an apocalyptic number.

It is an amenable number.

67784561 is a deficient number, since it is larger than the sum of its proper divisors (5214211).

67784561 is a wasteful number, since it uses less digits than its factorization.

67784561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5214210.

The product of its digits is 282240, while the sum is 44.

The square root of 67784561 is about 8233.1379801386. The cubic root of 67784561 is about 407.7340013744.

The spelling of 67784561 in words is "sixty-seven million, seven hundred eighty-four thousand, five hundred sixty-one".