61421823857 has 2 divisors, whose sum is σ = 61421823858. Its totient is φ = 61421823856.

The previous prime is 61421823847. The next prime is 61421823893. The reversal of 61421823857 is 75832812416.

61421823857 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42489164641 + 18932659216 = 206129^2 + 137596^2 .

It is a cyclic number.

It is not a de Polignac number, because 61421823857 - 2¹² = 61421819761 is a prime.

It is not a weakly prime, because it can be changed into another prime (61421823847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30710911928 + 30710911929.

It is an arithmetic number, because the mean of its divisors is an integer number (30710911929).

Almost surely, 2^61421823857 is an apocalyptic number.

It is an amenable number.

61421823857 is a deficient number, since it is larger than the sum of its proper divisors (1).

61421823857 is an equidigital number, since it uses as much as digits as its factorization.

61421823857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 645120, while the sum is 47.

The spelling of 61421823857 in words is "sixty-one billion, four hundred twenty-one million, eight hundred twenty-three thousand, eight hundred fifty-seven".