866737661 has 16 divisors (see below), whose sum is σ = 893356800. Its totient is φ = 840628800.

The previous prime is 866737643. The next prime is 866737679. The reversal of 866737661 is 166737668.

It is an interprime number because it is at equal distance from previous prime (866737643) and next prime (866737679).

It is a cyclic number.

It is not a de Polignac number, because 866737661 - 2¹⁴ = 866721277 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 (866737601) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2361500 + ... + 2361866.

It is an arithmetic number, because the mean of its divisors is an integer number (55834800).

Almost surely, 2^866737661 is an apocalyptic number.

It is an amenable number.

866737661 is a deficient number, since it is larger than the sum of its proper divisors (26619139).

866737661 is a wasteful number, since it uses less digits than its factorization.

866737661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 884.

The product of its digits is 1524096, while the sum is 50.

The square root of 866737661 is about 29440.4086418650. The cubic root of 866737661 is about 953.4455348920.

The spelling of 866737661 in words is "eight hundred sixty-six million, seven hundred thirty-seven thousand, six hundred sixty-one".