61670821 has 2 divisors, whose sum is σ = 61670822. Its totient is φ = 61670820.

The previous prime is 61670809. The next prime is 61670831. The reversal of 61670821 is 12807616.

61670821 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., 61449921 + 220900 = 7839^2 + 470^2 .

It is a cyclic number.

It is not a de Polignac number, because 61670821 - 2²¹ = 59573669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61670801) 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, 30835410 + 30835411.

It is an arithmetic number, because the mean of its divisors is an integer number (30835411).

Almost surely, 2^61670821 is an apocalyptic number.

It is an amenable number.

61670821 is a deficient number, since it is larger than the sum of its proper divisors (1).

61670821 is an equidigital number, since it uses as much as digits as its factorization.

61670821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 61670821 is about 7853.0771675821. The cubic root of 61670821 is about 395.0874580684.

The spelling of 61670821 in words is "sixty-one million, six hundred seventy thousand, eight hundred twenty-one".