61939639901 has 2 divisors, whose sum is σ = 61939639902. Its totient is φ = 61939639900.

The previous prime is 61939639889. The next prime is 61939639921. The reversal of 61939639901 is 10993693916.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 34040619001 + 27899020900 = 184501^2 + 167030^2 .

It is a cyclic number.

It is not a de Polignac number, because 61939639901 - 2²² = 61935445597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61939639921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30969819950 + 30969819951.

It is an arithmetic number, because the mean of its divisors is an integer number (30969819951).

Almost surely, 2^61939639901 is an apocalyptic number.

It is an amenable number.

61939639901 is a deficient number, since it is larger than the sum of its proper divisors (1).

61939639901 is an equidigital number, since it uses as much as digits as its factorization.

61939639901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2125764, while the sum is 56.

The spelling of 61939639901 in words is "sixty-one billion, nine hundred thirty-nine million, six hundred thirty-nine thousand, nine hundred one".