61785391 has 2 divisors, whose sum is σ = 61785392. Its totient is φ = 61785390.

The previous prime is 61785389. The next prime is 61785403. The reversal of 61785391 is 19358716.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61785391 - 2¹ = 61785389 is a prime.

Together with 61785389, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61785371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30892695 + 30892696.

It is an arithmetic number, because the mean of its divisors is an integer number (30892696).

Almost surely, 2^61785391 is an apocalyptic number.

61785391 is a deficient number, since it is larger than the sum of its proper divisors (1).

61785391 is an equidigital number, since it uses as much as digits as its factorization.

61785391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 40.

The square root of 61785391 is about 7860.3683755916. The cubic root of 61785391 is about 395.3319668303.

The spelling of 61785391 in words is "sixty-one million, seven hundred eighty-five thousand, three hundred ninety-one".