61778389 has 4 divisors (see below), whose sum is σ = 61795756. Its totient is φ = 61761024.

The previous prime is 61778383. The next prime is 61778407. The reversal of 61778389 is 98387716.

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 26471025 + 35307364 = 5145^2 + 5942^2 .

It is a cyclic number.

It is not a de Polignac number, because 61778389 - 2¹⁹ = 61254101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61778383) 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, 1194 + ... + 11179.

It is an arithmetic number, because the mean of its divisors is an integer number (15448939).

Almost surely, 2^61778389 is an apocalyptic number.

It is an amenable number.

61778389 is a deficient number, since it is larger than the sum of its proper divisors (17367).

61778389 is a wasteful number, since it uses less digits than its factorization.

61778389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17366.

The product of its digits is 508032, while the sum is 49.

The square root of 61778389 is about 7859.9229639991. The cubic root of 61778389 is about 395.3170322372.

The spelling of 61778389 in words is "sixty-one million, seven hundred seventy-eight thousand, three hundred eighty-nine".