67713521 has 4 divisors (see below), whose sum is σ = 70048500. Its totient is φ = 65378544.

The previous prime is 67713493. The next prime is 67713551. The reversal of 67713521 is 12531776.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 52417600 + 15295921 = 7240^2 + 3911^2 .

It is a cyclic number.

It is not a de Polignac number, because 67713521 - 2¹⁴ = 67697137 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (67713551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1167446 + ... + 1167503.

It is an arithmetic number, because the mean of its divisors is an integer number (17512125).

Almost surely, 2^67713521 is an apocalyptic number.

It is an amenable number.

67713521 is a deficient number, since it is larger than the sum of its proper divisors (2334979).

67713521 is a wasteful number, since it uses less digits than its factorization.

67713521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2334978.

The product of its digits is 8820, while the sum is 32.

The square root of 67713521 is about 8228.8225767725. The cubic root of 67713521 is about 407.5915129387.

The spelling of 67713521 in words is "sixty-seven million, seven hundred thirteen thousand, five hundred twenty-one".