61821889 has 2 divisors, whose sum is σ = 61821890. Its totient is φ = 61821888.

The previous prime is 61821887. The next prime is 61821923. The reversal of 61821889 is 98812816.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57881664 + 3940225 = 7608^2 + 1985^2 .

It is a cyclic number.

It is not a de Polignac number, because 61821889 - 2¹ = 61821887 is a prime.

Together with 61821887, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (61821887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30910944 + 30910945.

It is an arithmetic number, because the mean of its divisors is an integer number (30910945).

Almost surely, 2^61821889 is an apocalyptic number.

It is an amenable number.

61821889 is a deficient number, since it is larger than the sum of its proper divisors (1).

61821889 is an equidigital number, since it uses as much as digits as its factorization.

61821889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 55296, while the sum is 43.

The square root of 61821889 is about 7862.6896797470. The cubic root of 61821889 is about 395.4097952925.

The spelling of 61821889 in words is "sixty-one million, eight hundred twenty-one thousand, eight hundred eighty-nine".