61983638921 has 2 divisors, whose sum is σ = 61983638922. Its totient is φ = 61983638920.

The previous prime is 61983638903. The next prime is 61983638957. The reversal of 61983638921 is 12983638916.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 36810643321 + 25172995600 = 191861^2 + 158660^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61983638921 is a prime.

It is not a weakly prime, because it can be changed into another prime (61983638971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30991819460 + 30991819461.

It is an arithmetic number, because the mean of its divisors is an integer number (30991819461).

Almost surely, 2^61983638921 is an apocalyptic number.

It is an amenable number.

61983638921 is a deficient number, since it is larger than the sum of its proper divisors (1).

61983638921 is an equidigital number, since it uses as much as digits as its factorization.

61983638921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3359232, while the sum is 56.

The spelling of 61983638921 in words is "sixty-one billion, nine hundred eighty-three million, six hundred thirty-eight thousand, nine hundred twenty-one".