75724921 has 4 divisors (see below), whose sum is σ = 75744144. Its totient is φ = 75705700.

The previous prime is 75724889. The next prime is 75724933. The reversal of 75724921 is 12942757.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12942757 = 41 ⋅315677.

It is a cyclic number.

It is not a de Polignac number, because 75724921 - 2⁵ = 75724889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (75724951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1315 + ... + 12376.

It is an arithmetic number, because the mean of its divisors is an integer number (18936036).

Almost surely, 2^75724921 is an apocalyptic number.

It is an amenable number.

75724921 is a deficient number, since it is larger than the sum of its proper divisors (19223).

75724921 is a wasteful number, since it uses less digits than its factorization.

75724921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19222.

The product of its digits is 35280, while the sum is 37.

The square root of 75724921 is about 8702.0067225899. The cubic root of 75724921 is about 423.0706940698.

The spelling of 75724921 in words is "seventy-five million, seven hundred twenty-four thousand, nine hundred twenty-one".