67840561 has 4 divisors (see below), whose sum is σ = 67980352. Its totient is φ = 67700772.

The previous prime is 67840519. The next prime is 67840613. The reversal of 67840561 is 16504876.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 67840561 - 2¹¹ = 67838513 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 67840561.

It is not an unprimeable number, because it can be changed into a prime (67840511) 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, 69165 + ... + 70138.

It is an arithmetic number, because the mean of its divisors is an integer number (16995088).

Almost surely, 2^67840561 is an apocalyptic number.

It is an amenable number.

67840561 is a deficient number, since it is larger than the sum of its proper divisors (139791).

67840561 is a wasteful number, since it uses less digits than its factorization.

67840561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139790.

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 67840561 is about 8236.5381684297. The cubic root of 67840561 is about 407.8462531851.

The spelling of 67840561 in words is "sixty-seven million, eight hundred forty thousand, five hundred sixty-one".