68707521 has 21 divisors (see below), whose sum is σ = 103350801. Its totient is φ = 45655812.

The previous prime is 68707511. The next prime is 68707537. The reversal of 68707521 is 12570786.

The square root of 68707521 is 8289.

It is a perfect power (a square), and thus also a powerful number.

68707521 is a `hidden beast` number, since 68 + 70 + 7 + 521 = 666.

It is not a de Polignac number, because 68707521 - 2⁷ = 68707393 is a prime.

It is not an unprimeable number, because it can be changed into a prime (68707511) by changing a digit.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 223650 + ... + 223956.

Almost surely, 2^68707521 is an apocalyptic number.

68707521 is the 8289-th square number.

68707521 is the 4145-th centered octagonal number.

It is an amenable number.

68707521 is a deficient number, since it is larger than the sum of its proper divisors (34643280).

68707521 is an frugal number, since it uses more digits than its factorization.

68707521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632 (or 310 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

The cubic root of 68707521 is about 409.5762447091.

Multiplying 68707521 by its sum of digits (36), we get a square (2473470756 = 49734²).

The spelling of 68707521 in words is "sixty-eight million, seven hundred seven thousand, five hundred twenty-one".