68281521 has 16 divisors (see below), whose sum is σ = 113507328. Its totient is φ = 35470800.

The previous prime is 68281513. The next prime is 68281529. The reversal of 68281521 is 12518286.

It is an interprime number because it is at equal distance from previous prime (68281513) and next prime (68281529).

It is not a de Polignac number, because 68281521 - 2³ = 68281513 is a prime.

It is a super-2 number, since 2×68281521² = 9324732220146882, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (68281529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 147565 + ... + 148026.

It is an arithmetic number, because the mean of its divisors is an integer number (7094208).

Almost surely, 2^68281521 is an apocalyptic number.

It is an amenable number.

68281521 is a deficient number, since it is larger than the sum of its proper divisors (45225807).

68281521 is a wasteful number, since it uses less digits than its factorization.

68281521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295612.

The product of its digits is 7680, while the sum is 33.

The square root of 68281521 is about 8263.2633384154. The cubic root of 68281521 is about 408.7280050636.

The spelling of 68281521 in words is "sixty-eight million, two hundred eighty-one thousand, five hundred twenty-one".