61405 has 4 divisors (see below), whose sum is σ = 73692. Its totient is φ = 49120.

The previous prime is 61403. The next prime is 61409. The reversal of 61405 is 50416.

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 39204 + 22201 = 198^2 + 149^2 .

It is not a de Polignac number, because 61405 - 2¹ = 61403 is a prime.

It is a Duffinian number.

61405 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6136 + ... + 6145.

It is an arithmetic number, because the mean of its divisors is an integer number (18423).

2⁶¹⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

61405 is a deficient number, since it is larger than the sum of its proper divisors (12287).

61405 is a wasteful number, since it uses less digits than its factorization.

61405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12286.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 61405 is about 247.8003228408. The cubic root of 61405 is about 39.4518989342.

The spelling of 61405 in words is "sixty-one thousand, four hundred five".