75647721 has 16 divisors (see below), whose sum is σ = 109044800. Its totient is φ = 46484928.

The previous prime is 75647717. The next prime is 75647723. The reversal of 75647721 is 12774657.

It is not a de Polignac number, because 75647721 - 2² = 75647717 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 75647721.

It is not an unprimeable number, because it can be changed into a prime (75647723) 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, 15826 + ... + 20043.

It is an arithmetic number, because the mean of its divisors is an integer number (6815300).

Almost surely, 2^75647721 is an apocalyptic number.

It is an amenable number.

75647721 is a deficient number, since it is larger than the sum of its proper divisors (33397079).

75647721 is a wasteful number, since it uses less digits than its factorization.

75647721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35928.

The product of its digits is 82320, while the sum is 39.

The square root of 75647721 is about 8697.5698330051. The cubic root of 75647721 is about 422.9268745604.

The spelling of 75647721 in words is "seventy-five million, six hundred forty-seven thousand, seven hundred twenty-one".