61564421 has 2 divisors, whose sum is σ = 61564422. Its totient is φ = 61564420.

The previous prime is 61564417. The next prime is 61564423. The reversal of 61564421 is 12446516.

61564421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50268100 + 11296321 = 7090^2 + 3361^2 .

It is a cyclic number.

It is not a de Polignac number, because 61564421 - 2² = 61564417 is a prime.

It is a Sophie Germain prime.

Together with 61564423, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61564423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30782210 + 30782211.

It is an arithmetic number, because the mean of its divisors is an integer number (30782211).

Almost surely, 2^61564421 is an apocalyptic number.

It is an amenable number.

61564421 is a deficient number, since it is larger than the sum of its proper divisors (1).

61564421 is an equidigital number, since it uses as much as digits as its factorization.

61564421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5760, while the sum is 29.

The square root of 61564421 is about 7846.2998285816. The cubic root of 61564421 is about 394.8601139016.

The spelling of 61564421 in words is "sixty-one million, five hundred sixty-four thousand, four hundred twenty-one".