75320821 has 4 divisors (see below), whose sum is σ = 77072512. Its totient is φ = 73569132.

The previous prime is 75320803. The next prime is 75320827. The reversal of 75320821 is 12802357.

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 75320821 - 2⁹ = 75320309 is a prime.

It is a super-2 number, since 2×75320821² = 11346452152228082, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 75320821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (75320827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 875781 + ... + 875866.

It is an arithmetic number, because the mean of its divisors is an integer number (19268128).

Almost surely, 2^75320821 is an apocalyptic number.

It is an amenable number.

75320821 is a deficient number, since it is larger than the sum of its proper divisors (1751691).

75320821 is a wasteful number, since it uses less digits than its factorization.

75320821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1751690.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 75320821 is about 8678.7568810285. The cubic root of 75320821 is about 422.3167904234.

The spelling of 75320821 in words is "seventy-five million, three hundred twenty thousand, eight hundred twenty-one".