75387721 has 8 divisors (see below), whose sum is σ = 79478784. Its totient is φ = 71364480.

The previous prime is 75387709. The next prime is 75387727. The reversal of 75387721 is 12778357.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 75387721 - 2²³ = 66999113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (75387727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14665 + ... + 19126.

It is an arithmetic number, because the mean of its divisors is an integer number (9934848).

Almost surely, 2^75387721 is an apocalyptic number.

It is an amenable number.

75387721 is a deficient number, since it is larger than the sum of its proper divisors (4091063).

75387721 is a wasteful number, since it uses less digits than its factorization.

75387721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33911.

The product of its digits is 82320, while the sum is 40.

The square root of 75387721 is about 8682.6102642005. The cubic root of 75387721 is about 422.4417874351.

The spelling of 75387721 in words is "seventy-five million, three hundred eighty-seven thousand, seven hundred twenty-one".