68157731 has 4 divisors (see below), whose sum is σ = 71745000. Its totient is φ = 64570464.

The previous prime is 68157721. The next prime is 68157773. The reversal of 68157731 is 13775186.

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

It is a cyclic number.

It is not a de Polignac number, because 68157731 - 2¹⁴ = 68141347 is a prime.

It is a super-2 number, since 2×68157731² = 9290952590136722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68157701) 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, 1793606 + ... + 1793643.

It is an arithmetic number, because the mean of its divisors is an integer number (17936250).

Almost surely, 2^68157731 is an apocalyptic number.

68157731 is a deficient number, since it is larger than the sum of its proper divisors (3587269).

68157731 is a wasteful number, since it uses less digits than its factorization.

68157731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3587268.

The product of its digits is 35280, while the sum is 38.

The square root of 68157731 is about 8255.7695583150. The cubic root of 68157731 is about 408.4808564653.

The spelling of 68157731 in words is "sixty-eight million, one hundred fifty-seven thousand, seven hundred thirty-one".