61417978421 has 2 divisors, whose sum is σ = 61417978422. Its totient is φ = 61417978420.

The previous prime is 61417978409. The next prime is 61417978423. The reversal of 61417978421 is 12487971416.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60103915921 + 1314062500 = 245161^2 + 36250^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61417978421 is a prime.

It is a Sophie Germain prime.

Together with 61417978423, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 61417978421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61417978423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30708989210 + 30708989211.

It is an arithmetic number, because the mean of its divisors is an integer number (30708989211).

Almost surely, 2^61417978421 is an apocalyptic number.

It is an amenable number.

61417978421 is a deficient number, since it is larger than the sum of its proper divisors (1).

61417978421 is an equidigital number, since it uses as much as digits as its factorization.

61417978421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 677376, while the sum is 50.

The spelling of 61417978421 in words is "sixty-one billion, four hundred seventeen million, nine hundred seventy-eight thousand, four hundred twenty-one".