866250521 has 4 divisors (see below), whose sum is σ = 917206452. Its totient is φ = 815294592.

The previous prime is 866250491. The next prime is 866250547. The reversal of 866250521 is 125052668.

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 518017600 + 348232921 = 22760^2 + 18661^2 .

It is a cyclic number.

It is not a de Polignac number, because 866250521 - 2¹⁸ = 865988377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (866250821) 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, 25477940 + ... + 25477973.

It is an arithmetic number, because the mean of its divisors is an integer number (229301613).

Almost surely, 2^866250521 is an apocalyptic number.

It is an amenable number.

866250521 is a deficient number, since it is larger than the sum of its proper divisors (50955931).

866250521 is a wasteful number, since it uses less digits than its factorization.

866250521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50955930.

The product of its (nonzero) digits is 28800, while the sum is 35.

The square root of 866250521 is about 29432.1341563944. The cubic root of 866250521 is about 953.2668770270.

The spelling of 866250521 in words is "eight hundred sixty-six million, two hundred fifty thousand, five hundred twenty-one".