61868809 has 2 divisors, whose sum is σ = 61868810. Its totient is φ = 61868808.

The previous prime is 61868759. The next prime is 61868813. The reversal of 61868809 is 90886816.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51883209 + 9985600 = 7203^2 + 3160^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61868809 is a prime.

It is not a weakly prime, because it can be changed into another prime (61868869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30934404 + 30934405.

It is an arithmetic number, because the mean of its divisors is an integer number (30934405).

Almost surely, 2^61868809 is an apocalyptic number.

It is an amenable number.

61868809 is a deficient number, since it is larger than the sum of its proper divisors (1).

61868809 is an equidigital number, since it uses as much as digits as its factorization.

61868809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 165888, while the sum is 46.

The square root of 61868809 is about 7865.6728256393. The cubic root of 61868809 is about 395.5098026758.

The spelling of 61868809 in words is "sixty-one million, eight hundred sixty-eight thousand, eight hundred nine".