78625427521 has 2 divisors, whose sum is σ = 78625427522. Its totient is φ = 78625427520.

The previous prime is 78625427509. The next prime is 78625427579. The reversal of 78625427521 is 12572452687.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78503634225 + 121793296 = 280185^2 + 11036^2 .

It is a cyclic number.

It is not a de Polignac number, because 78625427521 - 2¹⁹ = 78624903233 is a prime.

It is not a weakly prime, because it can be changed into another prime (78625427501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39312713760 + 39312713761.

It is an arithmetic number, because the mean of its divisors is an integer number (39312713761).

Almost surely, 2^78625427521 is an apocalyptic number.

It is an amenable number.

78625427521 is a deficient number, since it is larger than the sum of its proper divisors (1).

78625427521 is an equidigital number, since it uses as much as digits as its factorization.

78625427521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1881600, while the sum is 49.

The spelling of 78625427521 in words is "seventy-eight billion, six hundred twenty-five million, four hundred twenty-seven thousand, five hundred twenty-one".