61710821 has 2 divisors, whose sum is σ = 61710822. Its totient is φ = 61710820.

The previous prime is 61710757. The next prime is 61710823. The reversal of 61710821 is 12801716.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53949025 + 7761796 = 7345^2 + 2786^2 .

It is a cyclic number.

It is not a de Polignac number, because 61710821 - 2⁶ = 61710757 is a prime.

Together with 61710823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61710823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30855410 + 30855411.

It is an arithmetic number, because the mean of its divisors is an integer number (30855411).

Almost surely, 2^61710821 is an apocalyptic number.

It is an amenable number.

61710821 is a deficient number, since it is larger than the sum of its proper divisors (1).

61710821 is an equidigital number, since it uses as much as digits as its factorization.

61710821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 26.

The square root of 61710821 is about 7855.6235271301. The cubic root of 61710821 is about 395.1728581682.

The spelling of 61710821 in words is "sixty-one million, seven hundred ten thousand, eight hundred twenty-one".