84071521 has 2 divisors, whose sum is σ = 84071522. Its totient is φ = 84071520.

The previous prime is 84071501. The next prime is 84071531. The reversal of 84071521 is 12517048.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79405921 + 4665600 = 8911^2 + 2160^2 .

It is a cyclic number.

It is not a de Polignac number, because 84071521 - 2⁵ = 84071489 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 84071521.

It is not a weakly prime, because it can be changed into another prime (84071501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42035760 + 42035761.

It is an arithmetic number, because the mean of its divisors is an integer number (42035761).

Almost surely, 2^84071521 is an apocalyptic number.

It is an amenable number.

84071521 is a deficient number, since it is larger than the sum of its proper divisors (1).

84071521 is an equidigital number, since it uses as much as digits as its factorization.

84071521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 84071521 is about 9169.0523501614. The cubic root of 84071521 is about 438.0761753905.

Adding to 84071521 its reverse (12517048), we get a palindrome (96588569).

It can be divided in two parts, 840 and 71521, that added together give a square (72361 = 269²).

The spelling of 84071521 in words is "eighty-four million, seventy-one thousand, five hundred twenty-one".