75678821 has 4 divisors (see below), whose sum is σ = 75697644. Its totient is φ = 75660000.

The previous prime is 75678817. The next prime is 75678833. The reversal of 75678821 is 12887657.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 28206721 + 47472100 = 5311^2 + 6890^2 .

It is a cyclic number.

It is not a de Polignac number, because 75678821 - 2² = 75678817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (75678871) 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, 680 + ... + 12321.

It is an arithmetic number, because the mean of its divisors is an integer number (18924411).

Almost surely, 2^75678821 is an apocalyptic number.

It is an amenable number.

75678821 is a deficient number, since it is larger than the sum of its proper divisors (18823).

75678821 is a wasteful number, since it uses less digits than its factorization.

75678821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18822.

The product of its digits is 188160, while the sum is 44.

The square root of 75678821 is about 8699.3575050115. The cubic root of 75678821 is about 422.9848239762.

The spelling of 75678821 in words is "seventy-five million, six hundred seventy-eight thousand, eight hundred twenty-one".