83815621 has 2 divisors, whose sum is σ = 83815622. Its totient is φ = 83815620.

The previous prime is 83815579. The next prime is 83815637. The reversal of 83815621 is 12651838.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55577025 + 28238596 = 7455^2 + 5314^2 .

It is a cyclic number.

It is not a de Polignac number, because 83815621 - 2⁷ = 83815493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (83815651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41907810 + 41907811.

It is an arithmetic number, because the mean of its divisors is an integer number (41907811).

Almost surely, 2^83815621 is an apocalyptic number.

It is an amenable number.

83815621 is a deficient number, since it is larger than the sum of its proper divisors (1).

83815621 is an equidigital number, since it uses as much as digits as its factorization.

83815621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11520, while the sum is 34.

The square root of 83815621 is about 9155.0871650684. The cubic root of 83815621 is about 437.6312461744.

The spelling of 83815621 in words is "eighty-three million, eight hundred fifteen thousand, six hundred twenty-one".