87381825521 has 2 divisors, whose sum is σ = 87381825522. Its totient is φ = 87381825520.

The previous prime is 87381825467. The next prime is 87381825563. The reversal of 87381825521 is 12552818378.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 82725264400 + 4656561121 = 287620^2 + 68239^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87381825521 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 87381825521.

It is not a weakly prime, because it can be changed into another prime (87381825121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43690912760 + 43690912761.

It is an arithmetic number, because the mean of its divisors is an integer number (43690912761).

Almost surely, 2^87381825521 is an apocalyptic number.

It is an amenable number.

87381825521 is a deficient number, since it is larger than the sum of its proper divisors (1).

87381825521 is an equidigital number, since it uses as much as digits as its factorization.

87381825521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1075200, while the sum is 50.

The spelling of 87381825521 in words is "eighty-seven billion, three hundred eighty-one million, eight hundred twenty-five thousand, five hundred twenty-one".