76731721 has 4 divisors (see below), whose sum is σ = 83707344. Its totient is φ = 69756100.

The previous prime is 76731701. The next prime is 76731731. The reversal of 76731721 is 12713767.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 76731721 - 2⁵ = 76731689 is a prime.

It is a super-3 number, since 3×76731721³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (76731701) 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, 3487795 + ... + 3487816.

It is an arithmetic number, because the mean of its divisors is an integer number (20926836).

Almost surely, 2^76731721 is an apocalyptic number.

It is an amenable number.

76731721 is a deficient number, since it is larger than the sum of its proper divisors (6975623).

76731721 is a wasteful number, since it uses less digits than its factorization.

76731721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6975622.

The product of its digits is 12348, while the sum is 34.

The square root of 76731721 is about 8759.6644342121. The cubic root of 76731721 is about 424.9374228512.

The spelling of 76731721 in words is "seventy-six million, seven hundred thirty-one thousand, seven hundred twenty-one".