78899521 has 2 divisors, whose sum is σ = 78899522. Its totient is φ = 78899520.

The previous prime is 78899501. The next prime is 78899543. The reversal of 78899521 is 12599887.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42719296 + 36180225 = 6536^2 + 6015^2 .

It is a cyclic number.

It is not a de Polignac number, because 78899521 - 2⁵ = 78899489 is a prime.

It is not a weakly prime, because it can be changed into another prime (78899501) 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, 39449760 + 39449761.

It is an arithmetic number, because the mean of its divisors is an integer number (39449761).

Almost surely, 2^78899521 is an apocalyptic number.

It is an amenable number.

78899521 is a deficient number, since it is larger than the sum of its proper divisors (1).

78899521 is an equidigital number, since it uses as much as digits as its factorization.

78899521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 49.

The square root of 78899521 is about 8882.5402335143. The cubic root of 78899521 is about 428.9020501831.

The spelling of 78899521 in words is "seventy-eight million, eight hundred ninety-nine thousand, five hundred twenty-one".